Treatment method and soil treatment method

ABSTRACT

A treatment method includes heating a treatment target object under reduced pressure in a hermetic zone to vaporize a component of the treatment target object, and opening a hermetic door and inserting a tube from a side of a treatment system for the vaporized component adjoining the hermetic zone with the hermetic door therebetween such that the tube shields the hermetic door from the hermetic zone to introduce the component vaporized from the treatment target object to the treatment system side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of and claims the benefit of priorityunder 35 U.S.C. § 120 from U.S. Ser. No. 09/711,362, filed Nov. 10,2000, which is a National Stage of International ApplicationPCT/JP99/02470, filed May 13, 1999. This application also claims thebenefit of priority under 35 U.S.C. § 119 from Japanese prioritydocuments, 10-148435 filed in Japan on May 13, 1998; 10-273417 filed inJapan on Sep. 28, 1998; and 10-377175 filed in Japan on Dec. 27, 1998.The entire contents of each of the applications listed above is hereinincorporated by reference.

TECHNICAL FIELD

The present invention relates to a treatment method and a soil treatmentmethod, and particularly relates to a treatment method and a soiltreatment method for treating an object to be treated containing heavymetals such as lead and noxious organic halides such as dioxins.Furthermore, the present invention relates to a treatment method capableof continuously treating an object to be treated containing metals andorganic substances.

BACKGROUND ART

An enormous amount of wastes which modern society holds continueincreasing day by day, and the establishment of effective treatmenttechnology is an urgent necessity.

Various useful substances are contained in wastes, but they are notseparated from the wastes because of difficulty in separation and thelike, and most of wastes are disposed of just as they are by reclamationor combustion. The useful substances in the wastes are required to beseparated and recovered, and recycled as much as possible since thereexist an energy problem and a problem of exhausting resources.

Meanwhile, noxious substances are also contained in the wastes. Thesenoxious substances is not only a cause of environmental disruption butalso one of the main causes of difficulty in recycling wastes.Therefore, if the noxious substances in the wastes can be removedeffectively, wastes can be recycled positively as a treasury ofresources, and influence on the environment and creatures can be held toa minimum.

As described above, the technology for treating wastes effectively needsto be established by all means to solve serious problems surroundingmodern society such as environmental pollution, disappearance ofresources, and shortage of energy source.

The types of wastes are, however, complicated and various in recentyears, and there are many complex wastes in which a plurality ofdifferent materials are integrated, and moreover there are wastescontaining noxious substances. To recycle such complex wastes asresources, it is required to selectively separate and recover usefulsubstances and noxious substances from the wastes in which a pluralityof different materials are integrated, but such treatment technology hasnot established yet.

From a different point of view, wastes become a treasury of resources ifnoxious substances can be separated therefrom. The so-called wastes arecalled so by relative value judgment. If recycling technology can beestablished and the cost necessary for recycling can be reduced, theyare no longer wastes but become resources.

DISCLOSURE OF THE INVENTION

It is required to address the aforesaid problems. Namely, there is aneed for a treatment method capable of effectively and economicallytreating an object having metals and organic substances as itscomponents.

Further, there is a need for a treatment method capable of suppressingthe production of dioxins, and particularly a treatment method capableof suppressing the production of organic halides containing dioxins inthermal decomposition treatment of waste automobiles and the like, andtreatment of refuse and wastes from factories and general households.Still further, there is a need for a treatment method capable oflowering the concentration of residual dioxins in a thermally decomposedresidue, burned residue, residual liquid, soil, sludge, and the likewhich contain noxious organic halides such as dioxins. Yet further,there is a need for production of clean soil from soil containingorganic halides such as dioxins. Furthermore, there is a need for atreatment method capable of cleaning soil and burned fly ashescontaminated by noxious substances such as organic halides such asdioxins, PCB, and coplanar PCB, and heavy metals.

According to an aspect, a treatment method includes heating a treatmenttarget object under reduced pressure in a hermetic zone to vaporize acomponent of the treatment target object, and opening a hermetic doorand inserting a tube from a side of a treatment system for the vaporizedcomponent adjoining the hermetic zone with the hermetic doortherebetween such that the tube shields the hermetic door from thehermetic zone to introduce the component vaporized from the treatmenttarget object to the treatment system side.

According to another aspect, a treatment method includes heating atreatment target object in a hermetic zone to thermally decompose acomponent of the treatment target object, and opening a hermetic doorand inserting a tube from a side of a treatment system for a componentof a gaseous emission produced by the thermal decomposition adjoiningthe hermetic zone with the hermetic door therebetween such that the tubeshields the hermetic door from the hermetic zone to introduce thegaseous emission to the treatment system side.

According to still another aspect, a treatment method includesintroducing a treatment target object into a hermetic zone, reducing apressure in the hermetic zone to extract a component of the treatmenttarget object, and opening a hermetic door and inserting a tube from aside of a treatment system for the extracted component adjoining thehermetic zone with the hermetic door therebetween such that the tubeshields the hermetic door from the hermetic zone to introduce theextracted component to the treatment system side.

According to yet another aspect, a treatment method includes heating atreatment target object containing a first metal under reduced pressurein a first hermetic zone to vaporize the first metal, inserting a tubefrom a second hermetic zone adjoining the first hermetic zone with ahermetic door therebetween such that the tube shields the hermetic doorfrom the first hermetic zone, and cooling the tube to condense the firstmetal.

According to further another aspect, a soil treatment method includesheating a soil containing a first metal under reduced pressure in afirst hermetic zone to vaporize the first metal, inserting a tube from asecond hermetic zone adjoining the first hermetic zone with a hermeticdoor therebetween such that the tube shields the hermetic door from thefirst hermetic zone, and cooling the tube to condense the first metalvaporized from the treatment target object.

According to further another aspect, a soil treatment method includesheating a soil containing a moisture, an organic substance, and a firstmetal in a first hermetic zone to vaporize the moisture and to performone of vaporizing and thermally decomposing of the organic substance,opening a first hermetic door and inserting a tube from a side of atreatment system for the moisture and one of the organic substance and athermal decomposition product of the organic substance connected to thefirst hermetic zone with the first hermetic door therebetween such thatthe tube shields the first hermetic door from the first hermetic zone tointroduce the vaporized moisture and one of the vaporized organicsubstance and the thermal decomposition product of the organic substanceto the treatment system side, vaporizing the first metal after thevaporization of the moisture and one of the vaporization and the thermaldecomposition of the organic substance, opening a second hermetic doorand inserting a tube from a side of a second hermetic zone adjoining thefirst hermetic zone with the second hermetic door therebetween such thatthe tube shields the second hermetic door from the second hermetic zoneto introduce the vaporized first metal to the second hermetic zone, andcooling the tube to condense at least the first metal.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view roughly showing an example of a treatmentapparatus according to an embodiment;

FIG. 2 is a diagram schematically showing the treatment apparatus of theembodiment illustrated in FIG. 1;

FIG. 3 is a diagram roughly showing another example of the treatmentapparatus of another embodiment;

FIG. 4 is a diagram schematically showing another example of thetreatment apparatus of another embodiment;

FIG. 5 is a diagram schematically showing another example of thetreatment apparatus of another embodiment;

FIG. 6 is a diagram schematically showing another example of thetreatment apparatus of another embodiment;

FIG. 7 is a diagram schematically showing the structure of a controlsystem for regulating the temperature, pressure, oxygen concentration ofthe treatment apparatus;

FIG. 8 and FIG. 9 are diagrams schematically showing a recovery systemincluding a recovery chamber connected to the treatment apparatus;

FIG. 10, FIG. 11, and FIG. 12 are diagrams roughly showing an example ofthe structure of the recovery chamber;

FIG. 13 is a graph showing temperature dependency of the boiling point(vapor pressure) of lead;

FIG. 14 is a diagram schematically showing the state of an untreatedmounting substrate as an object to be treated;

FIG. 15 is a diagram schematically showing the state of the mountingsubstrate in which its component resins are thermally decomposed;

FIG. 16 is a diagram schematically showing a state in which lead isvaporized;

FIG. 17 is a diagram schematically showing a state in which a circuitboard and electronic parts are separated;

FIG. 18 is a graph showing pressure dependency of the boiling points(vapor pressure) of various kinds of metals;

FIG. 19 is a diagram showing production free energy of various kinds ofoxides and their temperature dependency;

FIG. 20 is a diagram schematically showing an example of the treatmentapparatus;

FIG. 21 is a diagram schematically showing partitions of the treatmentapparatus;

FIG. 22 is a diagram schematically showing an example of the treatmentapparatus;

FIG. 23 is a diagram schematically showing the state of an untreatedcircuit board which is an example of the object to be treated;

FIG. 24 is a diagram schematically showing the state of the circuitboard of which the component resins are thermally decomposed;

FIG. 25 is a diagram schematically showing a state in which coppergathers in granular form by surface tension;

FIG. 26 is a diagram schematically showing untreated resin-coatedaluminum foil which is the object to be treated;

FIG. 27 is a diagram schematically showing the state of the resin-coatedaluminum foil of which the component resins are thermally decomposed;

FIG. 28 is a diagram schematically showing aluminum foil separated fromthe resin-coated aluminum foil;

FIG. 29 and FIG. 30 are graphs showing the relations between vaporpressure and temperature of various kinds of metals;

FIG. 31 is a diagram roughly showing an example of the treatmentapparatus;

FIG. 32 is a diagram schematically showing the structure of thetreatment apparatus illustrated in FIG. 31;

FIG. 33 is a diagram schematically showing an example of the structureof a thermal decomposition furnace;

FIG. 34 is a diagram schematically showing examples of the structure ofa gas decomposing device;

FIG. 35 is a diagram schematically showing examples of the structure ofa cooling tower;

FIG. 36 is a diagram showing a part of the structure of a gaseousemission treatment system in which a bag filter is connected at a stagesubsequent to the cooling tower;

FIG. 37 is a diagram roughly showing another example of the treatmentapparatus;

FIG. 38 is a diagram schematically showing the structure of thetreatment apparatus illustrated in FIG. 37;

FIG. 39 is a diagram schematically showing an example in which atreatment method according to another embodiment is applied to wastestreatment;

FIG. 40 is a diagram roughly and schematically showing an example of thestructure of shredding equipment;

FIG. 41, FIG. 42, FIG. 43, FIG. 44, and FIG. 45 are diagrams roughlyshowing the structure of the treatment apparatus;

FIG. 46 is a diagram roughly showing an example of the structure of awet filter;

FIG. 47 is a chart for explaining treatment conditions for the object tobe treated;

FIG. 48 is a chart showing measurement results of the concentration ofresidual dioxins in a heated residue;

FIGS. 49, 50, and 51 are diagrams roughly showing examples of thestructure of the treatment apparatus;

FIG. 52 is a schematic block diagram of a vacuum vaporization recoverydevice;

FIG. 53 is a detailed sectional view of a cooling and vacuum purgechamber portion of the vacuum vaporization recovery device;

FIG. 54 and FIG. 55 are diagrams showing a connecting method of arecovery retort and a cylinder for moving it forward and backward in thevacuum vaporization recovery device; and

FIG. 56 and FIG. 57 are diagrams roughly showing the structure of thetreatment apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

According to an aspect, a treatment apparatus adopts the followingstructure. Namely, the treatment apparatus according to this aspectincludes a first hermetic chamber having a first opening, a tube capableof inserting into the first opening, and the tube having a secondopening in an inserting direction, and a hermetic door capable ofopening and closing the first opening, and the door being shielded fromthe first hermetic chamber by the tube when the tube is inserted intothe first opening.

As the first hermetic chamber, a heating furnace, a reduced pressureheating furnace, and a reduced pressure heating furnace, for example,can be named. Such a hermetic chamber may have single chamber structure,and in addition, a plurality of such hermetic chambers may be arrangedwith doors between them. A purge chamber for purging a treatmentatmosphere for an object to be treated, a preheating chamber forpreheating the object to be treated, a cooling chamber for cooling theobject to be treated, and the like may be further provided at a stagebefore or after these hermetic chambers. When the pressure in a firsthermetic chamber is reduced, it is recommended that an exhaust systemfor exhausting the contents of the first hermetic chamber through afirst opening be provided. As an exhaust system, various kinds of vacuumpumps (a rotary pump, an oil diffusion pump, a mechanical booster pump,a turbo-molecular pump, a getter-ion pump, a liquid sealing pump, andthe like), a blower, a fan, and the like can be given. By such anexhaust system, the pressure in the first hermetic chamber can beregulated.

The first opening is provided in the first hermetic chamber. In thetreatment apparatus of this aspect, a gaseous emission produced from theobject to be treated by heating, pressure reduction, and the like in thefirst hermetic chamber is taken out through the tube inserted into thefirst opening and treated when the hermetic door is open. The gaseousemission is taken here to include gases, liquid drops, mist, solid fineparticles, and the like produced by heating of the object to be treated,pressure reduction, and the like. As the gaseous emission, gasesproduced by thermal decomposition or reaction of components of theobject to be treated, gases vaporized from components, and the like canbe named. Such a gaseous emission taken out of the first hermeticchamber is introduced to a predetermined treatment system. There arevarious types of the treatment system for the gaseous emission, and forexample, condensation, thermal decomposition, cracking, reforming(including hydroreforming), decomposition by a catalyst, decompositionby plasma or glow discharge, adsorption by various kinds of adsorbents,and trap by a dry filter or a wet filter (a liquid filter) can be shown.These first openings may be provided in plurality. Moreover, it isdesirable to provide this first opening separately from an opening forintroducing the object to be treated into the first hermetic chamber andan opening for taking the object to be treated out of the first hermeticchamber.

The hermetic door which is an openable and closeable shutter is placedat the first opening of the first hermetic chamber. It is recommendedthat the hermetic door be opened and closed, for example, by a drivemechanism such as a cylinder. When the operating direction of thehermetic door is substantially perpendicular to the normal direction ofan open face of the first opening, a joint for converting the pushingforce of the cylinder to the normal direction of the open face of thefirst opening may be provided at a connection portion of the cylinderand the hermetic door. Thus, the hermetic door can be pushed morestrongly in the normal direction of the first open face, therebyimproving hermetic sealing capability. The hermetic doors may beprovided multi-fold. It is desirable to cool a portion which a sealportion of the hermetic door touches when the hermetic door is closed.

In the treatment apparatus of this aspect, the hermetic door is opened,the tube is inserted into the first opening of the first hermeticchamber from outside, and the gaseous emission is taken out of thehermetic chamber to the outside through this tube. Moreover, it issuitable to provide a second hermetic chamber connected to the firsthermetic chamber via the first opening and insert the tube from thissecond hermetic chamber to the first opening. The tube has an externalshape such as fits the first opening. As the shape of the tube, anexample in which the tube has a third opening on a side opposite to thefirst hermetic chamber with the hermetic door therebetween when the tubeis inserted into the first opening is given. The third opening may beprovided so as to face the second opening or may be provided in a sideface of the tube.

Moreover, it is suitable that the tube has double structure and that arefrigerant such as nitrogen gas, air, or water is circulated betweenthe internal layer and the external layer, whereby the shieldingcapability of the hermetic door by the tube can be improved and the tubecan be cooled effectively. Also when a metal is vaporized from theobject to be treated and the vaporized metal is condensed in the tube,for example, condensation efficiency can be raised. In addition, thetube may be exchangeably provided. If so, the tube functions also as anexchangeable cartridge for recovering condensates.

When the tube is inserted into the first opening, the hermetic door isshielded from the first hermetic chamber by a zone between the secondopening and the third opening in the side face of the tube. Therefore,the gaseous emission can be prevented from condensing at the hermeticdoor or adhering thereto. Also when packing made of resin or the like isprovided at a seal portion of the hermetic door, for example, the damageof the seal portion of the hermetic door by heat of the gaseous emissioncan be prevented. Accordingly, the sealing capability of the hermeticdoor can be maintained. As described above, in the treatment apparatusof this aspect, an interface from the first hermetic chamber to theoutside is realized by the hermetic door and the tube.

It is suitable to provide a cylindrical sleeve at the first opening ofthe first hermetic chamber and to insert the tube into this sleeve. Witha change in the temperature inside the first hermetic chamber, the tube,the first opening, or the sleeve deforms due to thermal expansion or thelike. In some cases, the inserted tube can not be pulled out of thefirst opening or the tube by this thermal expansion. Therefore, it issuitable to make the thermal expansion coefficient of the sleeve equalto or larger than the thermal expansion coefficient of the tube, forexample. Furthermore, the tube may be selectively contracted by heatingthe sleeve or keeping the sleeve warm, and cooling the tube.

Moreover, it is desirable to make the sleeve of a material with highthermal conductivity such as carbon or metal. Thus, vaporized substancesfrom the object to be treated condense after going far away from thesecond opening of the tube. Accordingly, recovering efficiency can beraised.

In order to assist the moving operation of the tube, a means, placedalong the inserting direction of the tube, for guiding the inserting,attaching and detaching operation of the tube may be provided in thetreatment apparatus of this aspect. It is recommended that a guide rail,a guide roller, or the like, for example, be provided as the guide meansas required.

According to another aspect, the treatment apparatus further includesthe second hermetic chamber adjoining the first hermetic chamber withthe hermetic door therebetween, in which the tube is inserted into thefirst opening of the first hermetic chamber from the second hermeticchamber is given. Namely, the first hermetic chamber and the secondhermetic chamber are connected via the first opening in which thehermetic door is provided. The tube is inserted from the second hermeticchamber into the first opening. When the tube is inserted into the firstopening of the first hermetic chamber, the first hermetic chamber andthe second hermetic chamber are connected by the tube. When the tube isinserted into the first opening, the second opening of the tube ispositioned on the first hermetic chamber side of the hermetic door,whereas the third opening is positioned on the second hermetic chamberside of the hermetic door. Simultaneously, the hermetic door is shieldedfrom the first hermetic chamber and the second hermetic chamber by thetube.

In the second hermetic chamber, various kinds of treatments for thegaseous emission from the object to be treated can be performed. Forexample, the gaseous emission may be condensed by cooling the secondhermetic chamber or the tube. Moreover, the gaseous emission may bereformed or cracked in the second hermetic chamber. The tube or thesecond hermetic chamber may be provided between the first hermeticchamber and the exhaust system. In this case, the exhaust system isconnected to the first hermetic chamber via the tube or the secondhermetic chamber. The adoption of such structure enables a metalvaporized from the object to be treated under reduced pressure in thefirst hermetic chamber to be condensed in the tube or the secondhermetic chamber in a reduced pressure state. The treatment of thegaseous emission also can be performed in a reduced pressure state. Thedistance between molecules becomes longer under reduced pressure, andhence opportunities of reaction between molecules get fewer than undernormal pressure or under increased pressure. Even when components havingorganic halide producing capability such as aromatic hydrocarbon,halogen, and oxygen are contained in the gaseous emission, for example,the production of organic halides can be suppressed. Moreover, thereduced pressure state is suitable when the treatment of the gaseousemission by plasma discharge or the like is performed.

It is desirable to regulate the temperature in the second hermeticchamber (by cooling or heating). As the cooling structure of the secondhermetic chamber, for example, so-called water cooling jacket structurein which the second hermetic chamber has double structure and arefrigerant such as water is circulated in its external layer can beshown. Thus, vaporized substances or the gaseous emission from theobject to be treated can be condensed efficiently in the tube or thesecond hermetic chamber.

When the tube is provided as an exchangeable cartridge, it is suitable,for example, to provide a hermetically openable and closeable door forexchanging the tube in the second hermetic chamber, open the door, andexchange the tube. Incidentally, if the metal condensed in the tube orthe second hermetic chamber is taken out as it is into the atmosphere,the metal combusts strongly in some cases. Therefore, when the metal iscondensed and recovered, it is desirable to cool the condensed metal bya non-oxidizing gas before being taken out. Accordingly, it ispreferable that the second hermetic chamber include a means forsupplying a non-oxidizing gas.

In the treatment apparatus of this aspect, even when the second hermeticchamber is opened and the tube is taken out, the leakage of outside airinto the first hermetic chamber can be prevented since the hermeticsealing capability of the hermetic door is maintained. Hence, the tubecan be taken out while temperature conditions and pressure conditions inthe first hermetic chamber are maintained. This enables continuousoperation of the treatment apparatus and a rise in the productivity oftreatment. In this point, the treatment apparatus of this aspect differsmuch from a conventional treatment apparatus which needs to be stoppedwhen the gaseous emission or the condensates thereof are taken out of asystem

The exhaust system may be connected to the second hermetic chamber ormay be connected to the third opening of the tube. In the former case,the gaseous emission is led from the tube to the exhaust system throughthe second hermetic chamber. In the latter case, the gaseous emission isled from the third opening of the tube to the exhaust system directly.Moreover, it is desirable to connect the third opening of the tube andthe exhaust system as hermetically as possible. By connecting the thirdopening of the tube and the exhaust system directly, the condensation ofvaporized substances from the object to be treated in the secondhermetic chamber can be prevented.

In order to lead the gaseous emission from the object to be treated tothe outside by the tube while shielding the hermetic door by the tube,it is desirable that the tube fits the first opening or the sleeve asperfectly as possible. In some cases, the tube can not be easily pulledout of the sleeve due to thermal expansion of the sleeve, the tube, orthe condensates into the tube. If the third opening of the tube and theexhaust system are connected directly, an atmosphere in a space betweenthe second hermetic chamber and the tube is exhausted through the firsthermetic chamber and the tube even if there is a small gap between thetube and the sleeve, which can prevent the gaseous emission from flowinginto the space between the second hermetic chamber and the tube. Toconnect the third opening of the tube and the exhaust system, a pipe orpacking for connecting the third opening and the exhaust system when thetube is inserted into the first opening may be used.

Further, a means for performing regulation so that the pressure in thespace between the tube and the second hermetic chamber is higher thanthe pressure in the first hermetic chamber when the tube is insertedinto the first opening of the first hermetic chamber may be furtherprovided. Furthermore, a means for performing regulation so that thepressure in the first hermetic chamber is lower than the pressure in thespace between the tube and the second hermetic chamber and higher thanthe pressure in the tube when the tube is inserted into the firstopening of the first hermetic chamber may be provided. Namely, when thepressure in the first hermetic chamber is P1, the pressure in the spacebetween the tube and the second hermetic chamber is P2, and the pressurein the tube is P3, the entry of the vaporized substances into the spacebetween the tube and the second hermetic chamber from the first hermeticchamber can be prevented by letting P2>P1 and more preferably P2>P1>P3.

The aforesaid pressure regulation may be performed by supplying acarrier gas to the space between the tube and the second hermeticchamber. The carrier gas supplied to the space between the tube and thesecond hermetic chamber is led into the tube through the first hermeticchamber, and exhausted through the third opening of the tube. Therefore,the space between the tube and the second hermetic chamber is sealedfrom the first hermetic chamber by pressure. The space between the tubeand the second hermetic chamber communicates with a space in which thehermetic door is housed when being open, whereby the condensation of thevaporized substances from the object to be treated at the hermetic door,and more particularly at the seal portion thereof can be prevented.Moreover, a fitting margin of the tube and the sleeve is increased byadopting the aforesaid structure, which can prevent the tube and thesleeve from being locked by engagement.

Further, in the treatment apparatus of this aspect, a filter meansplaced between the second hermetic chamber (or the tube) and the exhaustmeans may be further provided. It is desirable to provide at least a wetfilter as the filter means. When the pressure in the first hermeticchamber is reduced by the exhaust system to thereby condense thevaporized substances from the object to be treated in a space betweenthe first hermetic chamber and the exhaust system, uncondensed vaporizedsubstances and condensed solid particles reach a vacuum pump in anycase. Thus, the vacuum pump is damaged or maintenance frequency israised. In the treatment apparatus of this aspect, the provision of awet filter for trapping fine particles, dust, and the like in gases by aliquid such as oil or water at a stage prior to the exhaust system canprevent the fine particles, dust, and the like from reaching the vacuumpump. An oil film filter in which a carrier in the form of cloth issoaked with oil can be used as the wet filter. The oil forms an oil filmby being sucked up by capillarity or the like. Dust and fine particleslead to the exhaust system are trapped by this oil film. Acid substancessuch as nitrogen oxides and sulfur oxides may be trapped by forming aliquid film of an aqueous solution such as an alkaline solution or thelike in place of oil. Also a liquid sealing pump such as a water sealingpump or an oil sealing pump may be used as the wet filter, in which casedust and fine particles are trapped by sealing liquid in the liquidsealing pump.

It is naturally suitable to place a dry filter such as a net or anon-woven fabric between the tube, the second hermetic chamber, or bothof them and the vacuum pump. Such a dry filter may be placed inside thetube or the second hermetic chamber. As for such a filter of the type totrap solids in a dry state, it is inevitable to let a part of thetrapped dust pass if the exhaust operation from the rear side by thevacuum pump is performed, and hence it is desirable to use it incombination with the wet filter.

According to another aspect, a treatment method includes heating anobject to be treated in a hermetic zone to thermally decompose acomponent of the object to be treated, and opening a hermetic door andinserting a tube from the side of a treatment system for a component ofa gaseous emission produced by the thermal decomposition adjoining thehermetic zone with the openable and closeable hermetic door therebetweenso that the hermetic door is shielded from the hermetic zone tointroduce the gaseous emission to the treatment system side.

According to still another aspect, a treatment method includesintroducing an object to be treated into a hermetic zone, reducing apressure in the hermetic zone to extract a component of the object to betreated, and opening a hermetic door and inserting a tube from the sideof a treatment system for the extracted component adjoining the hermeticzone with the openable and closeable hermetic door therebetween so thatthe hermetic door is shielded from the hermetic zone to introduce theextracted component to the treatment system side.

According to yet another aspect, a treatment method includes heating anobject to be treated containing a first metal under reduced pressure ina first hermetic zone to vaporize the first metal, inserting a tube froma second hermetic chamber adjoining the hermetic zone with an openableand closeable hermetic door therebetween so that the hermetic door isshielded from the first hermetic chamber, and cooling the tube tocondense the first metal.

According to further another aspect, a treatment apparatus includesheating a soil containing a first metal under reduced pressure in ahermetic zone to vaporize the first metal, inserting a tube from asecond hermetic chamber adjoining the hermetic zone with an openable andcloseable hermetic door therebetween so that the hermetic door isshielded from the first hermetic chamber, and cooling the tube tocondense the first metal vaporized from the object to be treated.

According to further another aspect, a treatment apparatus includesheating a soil containing a moisture, an organic substance, and a firstmetal in a hermetic zone to vaporize the moisture and vaporize orthermally decompose the organic substance, opening a first hermetic doorand inserting a tube from the side of a treatment system for themoisture, the organic substance, or a thermal decomposition product ofthe organic substance connected to the hermetic zone with the openableand closeable first hermetic door therebetween so that the firsthermetic door is shielded from the hermetic zone to introduce thevaporized moisture, the vaporized organic substance, or the thermaldecomposition product of the organic substance to the treatment systemside, vaporizing the first metal after the vaporization of the moistureand the organic substance and the thermal decomposition of the organicsubstance, opening a second hermetic door and inserting a tube from theside of a second hermetic chamber adjoining the hermetic zone with theopenable and closeable second hermetic door therebetween so that thesecond hermetic door is shielded from the hermetic zone to introduce thevaporized first metal to the second hermetic chamber, and cooling thetube to condense at least the first metal. It is desirable to cool aheated residue in the treatment apparatus by a cooling gas which issubstantially organic halide-free after the first metal is vaporizedfrom the soil.

Namely, provided is a method for taking the gaseous emission out of thehermetic zone while maintaining various conditions such as thetemperature, pressure, and oxygen concentration in the hermetic zonewhen heating of the object to be treated, pressure reduction, and thelike are performed in the hermetic zone. Therefore, the door placed atthe opening of the hermetic zone and capable of hermetically sealing thehermetic zone, and the tube to be inserted into and pulled out of theopening of the hermetic zone are adopted. As described above, when thedoor is opened and the gaseous emission is introduced from the hermeticzone to the treatment system, the tube is inserted into the opening, andthe door at a waiting position in an open state is shielded from thegaseous emission by this tube. The adoption of such structure canprevent the gaseous emission from condensing at and adhering to thehermetic door, and also can prevent a seal portion of the hermetic doorfrom being damaged by the heat of the gaseous emission, whereby thesealing capability of the hermetic door can be maintained.

Next, examples of a treatment apparatus will be explained. The techniquein which the gaseous emission from the object to be treated is taken outto the treatment system from the hermetic zone by the use of the tubeand the hermetic door can be applied to various kinds of treatmentapparatus which will be explained below.

To treat an object to be treated having resins and metals as itscomponents, a treatment system means for treating organic substancessuch as resins and a treatment system for vaporizing and recoveringmetals are provided.

According to an aspect, provided is a treatment apparatus for treatingan object to be treated having resins and metals as its components,including a first hermetic zone including a temperature regulating meansand a pressure regulating means for regulating a temperature and apressure so that the resins in the object to be treated are thermallydecomposed selectively, a second hermetic zone partitioned from thefirst hermetic zone by an openable and closeable partition and includinga temperature regulating means and a pressure regulating means forregulating a temperature and a pressure so that a metal in the object tobe treated is selectively vaporized, a first treatment system connectedto the first hermetic zone and treating gases produced by the thermaldecomposition of the resins, and a second treatment system connected tothe second hermetic zone and treating the metal vaporized from theobject to be treated.

In the first hermetic zone, organic substances such as resins arethermally decomposed selectively so that metals (except mercury) in theobject to be treated are not vaporized. Generally, when the object to betreated is complicated, there is a possibility that the object to betreated is partially oxidized or reduced, or a phase equilibrium statechanges during treatment, but it is only required that the componentmetals (except mercury only) of the object to be treated remain in theobject to be treated or the first hermetic zone without being vaporized.Moreover, a temperature regulating means and a pressure regulating meansfor decomposing organic substances while performing maintenance so thatthe component metals of the object to be treated are not substantiallyoxidized may be provided.

It is recommended to use a heating means and a temperature measuringmeans as the temperature regulating means. It is suitable to select theheating means from various kinds of heating such as convention heating,radiation heating, and the like as required or use them in combinationas the heating means. For example, resistance heating by a sheathedheater, a radiant tube, or the like may be used, or gas, heavy oil,light oil, or the like may be combusted. Besides, an induction heatingmeans may be used. As the temperature measuring means, various kinds oftemperature sensors may be used.

In the first hermetic zone, organic substances such as resins areselectively decomposed and vaporized (including vaporization afterliquefaction) or carbonized on temperature and pressure conditions suchthat metals in the object to be treated are not oxidized nor vaporizedmuch.

Gases produced by the decomposition of resins and vaporized are treatedin the first treatment system, and for example, recovered. It issuitable to combust the recovered decomposition products of the resinsand use them as a heating means. As described above, generally, when theobject to be treated is complicated and abundant, there is a possibilitythat the object to be treated is partially oxidized or reduced, or aphase equilibrium state changes during treatment. For example, whencomponent metals of the object to be treated are mixed in the firsttreatment system for recovering decomposition products of resins, it isrecommended that the metals be separated and recovered in the subsequentprocess.

It is recommended that an exhaust means or a pressurizing means and apressure measuring means be used as the pressure regulating means. It issuitable to use various kinds of vacuum pumps such as a rotary pump, anoil diffusion pump, and a booster pump as the exhaust means. As thepressurizing means, a gas may be introduced into the system, forexample, from a gas reservoir. It is recommended that a Bourdon tube, aPirani gauge, or the like be used as the pressure measuring meansaccording to the degree of vacuum to be measured.

Further, a purge zone may be provided adjacent to the first hermeticzone. It is suitable that a pressure regulating means such as an exhaustsystem or a pressurization system and a temperature regulating means forpreheating or cooling the object to be treated are provided.Furthermore, a carrier gas introduction system for purging gas in thesystem may be provided, and the carrier gas introduction system mayserve also as a pressurization system. The object to be treated isintroduced to the first hermetic zone from the outside of the apparatusthrough the purge zone.

By providing the purge zone, the first hermetic zone is isolated fromthe outside of the apparatus on the occasion of the introduction of theobject to be treated to the first hermetic zone. In addition, thecontents of the first hermetic zone are always exhausted and the firsthermetic zone is maintained in a reduced pressure state, whereby theburden imposed on the vacuum pump is lightened.

Similarly, a purge zone may be provided adjacent to the second hermeticzone. The object to be treated is taken out of the second hermetic zoneto the outside of the apparatus through the purge zone.

By providing the purge zone at the stage following the second hermeticzone, the second hermetic zone is isolated from the outside of theapparatus when the object to be treated is taken out of the secondhermetic zone. Accordingly, the contents of the second hermetic zone arealways exhausted and the second hermetic zone is maintained in a reducedpressure state, whereby the burden imposed on the vacuum pump islightened. Moreover, the object to be treated can be kept being shieldedfrom the outside air until the temperature of the heated object to betreated is cooled to a temperature such that the object to be treated isnot oxidized even under atmospheric pressure.

Namely, the purge zone functions as a buffer zone between the outside ofthe apparatus and the first and second hermetic zones in terms of themaintenance of the apparatus and in terms of the maintenance of theobject to be treated.

The first hermetic zone and the second hermetic zone of the treatmentapparatus are partitioned by an openable and closeable partition. Thispartition maintains the hermetic sealing capability of each of the zonesand the heat insulating properties of each of the zones. For example, avacuum door for maintaining hermetic sealing capability and a heatinsulating door for maintaining heat insulating properties may be usedin combination. If the first and second hermetic zones are partitionedby partitions in order of a heat insulating door, a vacuum door, and aheat insulating door, the hermetic sealing capability and heatinsulating properties of each of the zones are maintained. The aforesaidplacement of the heat insulating doors between the vacuum door and thezones partitioned by this vacuum door can protect the vacuum door fromthermal load even when large thermal load is imposed on the vacuum door.In this case, the vacuum door is protected from heat of the first andsecond hermetic zones.

These partitions are of course placed between the outside of theapparatus and the purge zone, between the purge zone and the firsthermetic zone, and between the second hermetic zone and the purge zone,but it is recommended that the kind of partition to be placed bedesigned as required. For example, when the thermal load of the purgechamber is small, the vacuum door may be placed.

In the first hermetic zone to which the object to be treated isintroduced, temperature and pressure conditions are regulated so thatresins are decomposed while the state of metals in the object to betreated is maintained. The temperature and pressure conditions may beset previously or may be controlled by feeding back measured values oftemperature and pressure to the heating means and the pressureregulating means. This applies to the second hermetic zone, too.

If the pressure inside the first hermetic chamber is reduced, the oxygenconcentration is also lowered, and thus the object to be treated isnever oxidized abruptly by heating. Moreover, although a large quantityof gases are produced by decomposition of resins by heating, oxygen ishardly produced even the resins are decomposed, generally. Furthermore,decomposition products of the resins are easily vaporized.

Meanwhile, if the pressure is reduced, the thermal conductivity insidethe hermetic zone is lowered. If a non-oxidizing atmosphere ismaintained in the first hermetic zone, the object to be treated is notsubstantially oxidized even under atmospheric pressure or underincreased pressure. Thus, if a non-oxidizing atmosphere is maintained inthe first hermetic zone, pressurization is possible and the thermalconductivity inside the system is raised.

The first treatment system treats a gaseous emission containing gasesproduced by decomposition of organic substances composing the object tobe treated, in which case resins may be synthetic resins, naturalresins, or a mixture of these resins.

A liquefying device for condensing and liquefying gases may be used asthe first treatment system. When gases such as halogen and organichalides are contained in the gases produced by decomposition of resins,the gases may be decomposed, for example, by using a catalyst or thelike.

As described above, heavy oil, light oil, and the like recovered by thefirst treatment system may be used for heating in the first or thesecond hermetic zone.

Moreover, the first treatment systems may be provided in plural lines orconnected in multiple tiers.

Most of resin components of the object to be treated are decomposed inthe first hermetic zone, and gases produced by the decomposition arerecovered or made innoxious. Accordingly, metals in the object to betreated exist in the object to be treated without being vaporized.Meanwhile, most of resins in the object to be treated exist as carbides.The object to be treated is moved from the first hermetic zone to thesecond hermetic zone in this state.

In the treatment apparatus, the object to be treated which is heated inthe first hermetic container is introduced into the second hermetic zonewithout being cooled. Thus, energy to be supplied to the second hermeticzone is greatly saved, and heating time is shortened.

In the second hermetic zone into which the object to be treated isintroduced, temperature and pressure conditions are regulated so thatmetals in the object to be treated are vaporized. If the pressure in thesecond hermetic zone is reduced, the metals in the object to be treatedare vaporized at a lower temperature than under normal pressure.Moreover, oxygen concentration is lowered and a non-oxidizing atmospherecomes to be maintained in the second hermetic zone, and thus themetallic state of the vaporized metal is maintained.

For example, the boiling point of Zn at 760 Torr is 1203K, whereas theboiling point thereof at 1 Torr is 743K, and the boiling point thereofat 10⁻⁴ Torr is 533K.

Additionally, the boiling point of Pb at 760 Torr (1 atm) is 2017K,whereas the boiling point thereof at 10⁻¹ Torr is 1100K, and the boilingpoint thereof at 10⁻³ Torr is 900K.

As described above, metals are selectively vaporized according to thetemperature and pressure conditions in the second hermetic zone.

When being introduced in the second hermetic chamber, most of resins inthe object to be treated have been turned into carbides, and hence gasesto be produced by decomposition are hardly produced even if a metal isvaporized from the object to be treated. Therefore, the vaporized metalis recovered at high purity in a still metallic state, and the loadimposed on the vacuum pump is lightened.

The second recovery means is to recover the metal vaporized in thesecond hermetic zone as above.

For example, it is suitable to connect a recovery chamber having anexhaust system to the second hermetic zone, and to cool the vaporizedmetal to its melting point or lower, and condense and recover it. Theinterior of the recovery chamber may have counter-current structure orhelical structure, for example. Alternatively, a valve or an openableand closeable partition may be provided between the recovery chamber andthe second hermetic zone and between the recovery chamber and theexhaust system. Even when the vaporized metal is condensed and recoveredcontinuously, or condensed and recovered by batch processing, recoveryefficiency increases if the retention time of the vaporized metal in therecovery chamber is lengthened.

N2 or a rare gas as a carrier gas may be introduced into the secondhermetic zone. The vaporized metal is efficiently introduced into therecovery chamber by the carrier gas.

The second recovery means may be provided in plural lines. It issuitable to recover the same metal by means of the plurality of secondrecovery means, or it is suitable that a plurality of metals areselectively vaporized by regulating the temperature and pressure in thesecond hermetic zone stepwise and recovered by switching the plurallines of second recovery means.

Further, the second recovery means may be connected in multiple tiers.

As described above, the treatment apparatus treats an object to betreated having resins and metals as its components. The treatmentapparatus enables the treatment of the object to be treated havingresins and metals as its components by including the first hermetic zonefor decomposing the component resins of the object to be treated at astage prior to the second hermetic zone for vaporizing the componentmetals of the object to be treated. A large quantity of gases producedby decomposition of resins of the object to be treated in the hermeticzone are subjected to treatments such as cracking, catalytic reaction,neutralization, and adsorption in the treatment system connected to thefirst hermetic zone. Thus, sufficient heating and pressure reductionsuch that the metals are vaporized can be performed in the secondhermetic zone.

Further, in the first hermetic zone, the resins are thermally decomposedselectively in such a condition that the metals in the object to betreated are not oxidized nor vaporized much, and thus the metals areseparated and recovered from the object to be treated in a metallicstate.

Furthermore, the treatment apparatus of this aspect may further includean oxygen concentration regulating means for regulating the oxygenconcentration in the first hermetic zone. For example, it is suitable todetect the oxygen concentration in the first hermetic zone and regulatethe temperature and pressure in the first hermetic zone, and the flowrate of a carrier gas according to the detected oxygen concentration.

The component resins of the object to be treated can be thermallydecomposed more selectively by providing the oxygen concentrationregulating means. Moreover, in the first hermetic zone, a temperatureregulating means, a pressure regulating means, and an oxygenconcentration regulating means for thermally decomposing resinsselectively while maintaining the first hermetic zone so that metals arenot substantially oxidized.

This treatment apparatus includes the oxygen concentration regulatingmeans in the first hermetic zone. Owing to this oxygen concentrationregulating means, the oxygen concentration inside the first hermeticzone can be regulated independently of the total pressure inside thefirst hermetic zone.

The degree of freedom of treatment in the first hermetic zone is raisedby regulating the oxygen concentration in the first hermetic zone. Forexample, the state of component metals of the object to be treated canbe maintained without the thermal conductivity inside the first hermeticzone being lowered. In addition, resins can be decomposed morepositively under pressurized conditions.

As the oxygen concentration regulating means, for example, an oxygenconcentration sensor which is an oxygen concentration measuring meansand a carrier gas introduction system may be used.

As the oxygen concentration sensor, for example, a so-called zirconiasensor using zirconia (zirconium oxide) may be used, or the absorptionof CO and CO₂, for example, may be measured by infrared spectroscopy.Besides, GC-MS may be used. It is suitable that the oxygen concentrationsensor is selected from them as required or they are used incombination.

A rare gas such as N₂ or Ar may be used as a carrier gas. Owing to thiscarrier gas, not only the oxygen concentration in the hermetic zone isregulated, but also gases produced by decomposition of resins areefficiently led to the first recovery means. Moreover, the oxygenconcentration regulating means may serve also as a pressure regulatingmeans, and besides may detect the concentration of halogen such aschlorine, for example, without limiting to that of oxygen and regulatethe temperature and pressure in the first hermetic zone, and the flowrate of a carrier gas according to the detected chlorine concentration.Thus, the production or the recomposition of dioxins can be suppressed.

A plurality of second hermetic zones may be provided. Namely, atreatment apparatus for treating an object to be treated having resins,a first metal, and a second metal as its components may include a firsthermetic zone including a temperature regulating means, a pressureregulating means, and an oxygen regulating means for thermallydecomposing the resins selectively, a second hermetic zone partitionedfrom the first hermetic zone by an openable and closeable partition andincluding a temperature regulating means and a pressure regulating meansfor vaporizing the first metal in the object to be treated selectively,a third hermetic zone partitioned from the second hermetic zone by anopenable and closeable partition and including a temperature regulatingmeans and a pressure regulating means for vaporizing the second metal inthe object to be treated selectively, a first recovery means, connectedto the first hermetic zone, for recovering gases produced bydecomposition of the resins, a second recovery means, connected to thesecond hermetic zone, for recovering the first metal vaporized from theobject to be treated, and a third recovery means, connected to the thirdhermetic zone, for recovering the second metal vaporized from the objectto be treated.

The configuration of this treatment apparatus includes a plurality ofsecond hermetic zones. By providing the plurality of second hermeticzones, a plurality of metals contained in the object to be treated areselectively vaporized and recovered.

Furthermore, according to another aspect, provided is a treatmentapparatus for treating an object to be treated having resins and metalsas its components, including a hermetic container holding the object tobe treated therein and including a temperature regulating means, apressure regulating means, and an oxygen regulating means, a firstrecovery means, connected to the hermetic container, for recoveringgases produced by thermal decomposition of the resins when thetemperature and oxygen concentration in the hermetic container areregulated so that the resins in the object to be treated are thermallydecomposed, and a second recovery means, connected to the hermeticcontainer, for recovering a metal vaporized from the object to betreated when the temperature and pressure in the hermetic container areregulated so that a first metal in the object to be treated isselectively vaporized. It may further include a third recovery means,connected to the hermetic container, for recovering a second metalvaporized from the object to be treated when the temperature andpressure in the hermetic container are regulated so that the secondmetal in the object to be treated is selectively vaporized.

The first recovery means may recover gases produced by decomposition ofthe resins when the temperature and oxygen concentration in the hermeticcontainer are regulated so that the first and second metals in theobject to be treated are not substantially oxidized and the resins arethermally decomposed selectively.

The treatment apparatus of this aspect includes a means for changingconditions in one hermetic container and a plurality of recovery meanscorresponding to conditions in the system, whereas the treatmentapparatus according to the aforesaid aspect includes a plurality ofhermetic zones different in conditions such as temperature, pressure,and oxygen concentration conditions in the hermetic container.

Similarly to the treatment apparatus according to the aforesaid aspect,it is recommended that a heating means, a temperature sensor, and thelike be used as the temperature regulating means in the hermeticcontainer, that is, the temperature regulating means for the object tobe treated. Also as for heating, it is suitable to select one fromvarious kinds of heating means such as convention, radiation, and thelike as required or use them in combination.

Also concerning the pressure regulating means, similarly to thetreatment apparatus according to the aforesaid aspect, it is recommendedthat an exhaust means, a pressurizing means and a pressure measuringmeans be used. It is suitable to use various kinds of vacuum pumps suchas a rotary pump, an oil diffusion pump, and a booster pump as theexhaust means. As the pressurizing means, a gas may be introduced intothe system, for example, from a gas reservoir. It is recommended that aBourdon tube, a Pirani gauge, or the like be used as the pressuremeasuring means according to the degree of vacuum to be measured.

Also concerning the oxygen concentration regulating means, it isrecommended that an oxygen concentration sensor and a carrier gasintroduction system be used similarly.

Moreover, it is recommended that the recovery means also be provided inthe same manner as in the treatment apparatus of the aforesaid aspect.

Namely, a liquefying device for condensing and recovering gases producedby decomposition of resins, for example, may be provided as the firstrecovery system. Oil obtained by this liquefying device may be used as aheating means.

Further, as for the second and third recovery means, for example, arecovery chamber having an exhaust system is connected to the hermeticzone, and the metal vaporized in this chamber may be cooled to itsmelting point or lower, condensed, and recovered. The interior of therecovery chamber may have counter-current structure or helicalstructure, for example. Alternatively, a valve or an openable andcloseable partition may be provided between the recovery chamber and thesecond hermetic zone and between the recovery chamber and the exhaustsystem. Namely, it is suitable that after the metal vaporized from theobject to be treated is introduced into the recovery chamber, thechamber is closed and cooled and thereby the metal is condensed andrecovered.

According to another aspect, provided is a treatment system for treatingan object to be treated having lead as its component, including ahermetic container for holding the object to be treated therein, atemperature regulating means for regulating the temperature in thehermetic container, a pressure regulating means for regulating thepressure in the hermetic container, a control means for controlling thetemperature regulating means and the pressure regulating means so thatlead in the object to be treated is selectively vaporized, and arecovery means, connected to the hermetic container, for recovering thelead vaporized from the object to be treated. The structure in which theaforesaid tube and hermetic door are combined can be adopted as therecovery means.

Also, it may include a hermetic container for holding an object to betreated having lead and resins as its components therein, a temperatureregulating means for regulating the temperature in the hermeticcontainer, a pressure regulating means for regulating the pressure inthe hermetic container, a first control means for controllingtemperature regulating means and the pressure regulating means so thatthe temperature and pressure in the hermetic container are regulatedsuch that the resins are selectively vaporized while the lead in theobject to be treated is maintained so as not to be substantiallyvaporized, a second control means for controlling the temperatureregulating means and the pressure regulating means so that thetemperature and pressure in the hermetic container are regulated suchthat the lead in the object to be treated is selectively vaporized, afirst recovery means, connected to the hermetic container, forrecovering gases produced by decomposition of the resins, and a secondrecovery means, connected to the hermetic container, for recovering thelead vaporized from the object to be treated.

According to another aspect, provided is a treatment system for treatingthe object to be treated having lead and resins as its components,including a hermetic container for holding the object to be treatedtherein, a temperature regulating means for regulating the temperaturein the hermetic container, a pressure regulating means for regulatingthe pressure in the hermetic container, an oxygen concentrationregulating means for regulating the oxygen concentration in the hermeticcontainer, a first control means for controlling the temperatureregulating means and the oxygen concentration regulating means so thatthe resins are thermally decomposed selectively, a second control meansfor controlling the temperature regulating means and the pressureregulating means so that the temperature and pressure are regulated suchthat the lead in the object to be treated is selectively vaporized, afirst recovery means, connected to the hermetic container, forrecovering gases produced by thermal decomposition of the resins, and asecond recovery means, connected to the hermetic container, forrecovering the lead vaporized from the object to be treated.

The first control means may control the temperature regulating means andthe oxygen concentration regulating means so that the temperature andoxygen concentration in the hermetic container are regulated such thatthe resins are thermally decomposed selectively while the lead in theobject to be treated is maintained so as not to be substantiallyoxidized.

According to another aspect, a treatment method includes introducing anobject to be treated having lead as its component into a hermeticcontainer and hermetically sealing the hermetic container, regulatingthe temperature and pressure in the hermetic container so that the leadin the object to be treated is selectively vaporized, and recovering thelead vaporized from the object to be treated.

Moreover, the treatment method may include introducing an object to betreated having lead and resins as its components into a hermeticcontainer and hermetically sealing the hermetic container, a firstcontrol step of regulating the temperature and pressure in the hermeticcontainer so that the resins in the object to be treated are thermallydecomposed selectively, a second control step of regulating thetemperature and pressure in the hermetic container so that the lead inthe object to be treated is selectively vaporized, a first recovery stepof recovering gases produced by the thermal decomposition of the resins,and a second recovery step of recovering the lead vaporized from theobject to be treated.

According to another aspect, a treatment method includes introducing anobject to be treated having lead and resins as its components into ahermetic container and hermetically sealing the hermetic container, afirst control step of regulating the temperature and oxygenconcentration in the hermetic container so that the resins are thermallydecomposed selectively, a second control step of regulating thetemperature and pressure in the hermetic container so that the lead inthe object to be treated is selectively vaporized, a first recovery stepof recovering gases produced by the thermal decomposition of the resins,and a second recovery step of recovering the lead vaporized from theobject to be treated.

Additionally, in the first control step, the temperature and oxygenconcentration in the hermetic container may be regulated so that thelead in the object to be treated is not substantially oxidized and sothat the resins are thermally decomposed selectively.

These treatment systems and treatment methods make it possible toseparate and recover lead from an object to be treated containing lead.

In the first control step, the oxygen concentration in the hermeticcontainer, for example, may be regulated at about 10 vol % or lower. Theoxidation of lead can be prevented by regulating the oxygenconcentration.

Further, in the first control step, the temperature in the hermeticcontainer, for example, may be regulated in the range of 323K to 1073K.

Furthermore, in the first control step, the pressure in the hermeticcontainer, for example, may be regulated at about 760 Torr to about 10Torr. Lead is vaporized at a lower temperature by regulating thepressure.

In the second control step, for example, the pressure in the hermeticcontainer may be regulated at about 7.6×10² Torr to about 7.6×10³ Torr.The thermal decomposition of resins is promoted by thermally decomposingthe resins selectively by pressurization.

Further, in the second control step, for example, the temperature in thehermetic container may be regulated in the range of 713K to 2273K.

These treatment system and method basically introduce an object to betreated into a hermetic container, regulating the temperature, pressure,and oxygen concentration in the hermetic container to vaporize lead inthe object to be treated selectively, and separate and recover it fromthe object to be treated. Moreover, also concerning each of metals otherthan lead, it is suitable that the interior of the hermetic container iscontrolled on predetermined temperature and pressure conditions suchthat the metal is selectively vaporized, and that the metal is separatedand recovered from the object to be treated.

When the object to be treated contains lead and resins, resinousportions are first thermally decomposed (gasified, liquefied, orcarbonized) selectively by heating the object to be treated on such acondition that lead is not vaporized nor oxidized, then the lead isselectively vaporized, and the vaporized lead is recovered in a metallicstate. In this case, the resins may be synthetic resins, natural resins,or a mixture of these resins. Generally, the greater part of athermoplastic resin can be vaporized or liquefied by heating andrecovered, whereas the greater part of a thermoset resin is carbonizedor vaporized. In either case, the lead can be recovered positively bythermally decomposing the component resins of the object to be treatedselectively.

The treatment apparatus of the aforesaid aspect, for example, may beused for an apparatus portion of the treatment system. Namely, forexample, selective thermal decomposition of resins and vaporization oflead may be performed by regulating stepwise conditions such astemperature, pressure, and oxygen concentration in one hermeticcontainer. Moreover, selective thermal decomposition of resins andvaporization of lead may be performed by providing a plurality ofhermetic zones different in conditions such as temperature, pressure,and oxygen concentration and opening and closing partitions whichpartition respective hermetic zones to transfer the object to be treatedsequentially.

It is recommended that a heating means and a temperature measuring meansbe used as the temperature regulating means. As the heating means, forexample, resistance heating by a sheathed heater, or the like may beused, or oil such as heavy oil or light oil may be combusted. Besides,an induction heating means may be used. It is recommended that variouskinds of thermometers may be used as the temperature measuring means.

By controlling the temperature, pressure, oxygen concentration in thehermetic container, the resins are thermally decomposed selectively andvaporized (including vaporization after liquefaction) or carbonized ontemperature and pressure conditions such as lead in the object to betreated is not oxidized not vaporized. Gases produced by thermaldecomposition of the resins and vaporized are recovered in the firstrecovery means, and it is suitable to combust the recovereddecomposition products of the resins and use them as a heating means.

It is recommended that an exhaust means or a pressurizing means and apressure measuring means be used as the pressure regulating means. It issuitable to use various kinds of vacuum pumps such as a rotary pump, anoil diffusion pump, and a booster pump as the exhaust means as requireddepending on the degree of vacuum, exhaust capacity, and the like. Asthe pressurizing means, a gas may be introduced into the system, forexample, from the gas reservoir.

Moreover, a carrier gas may be introduced into the hermetic container.This carrier gas may be used as the pressurizing means, for example, byregulating a valve of exhaust system and introduction flow rate.

It is recommended that a Bourdon tube, a Pirani gauge, or the like beused as the pressure measuring means according to the degree of vacuumto be measured.

Also in the treatment system, in addition to the temperature regulatingmeans and the pressure regulating means, the oxygen concentrationregulating means for regulating the oxygen concentration in the hermeticcontainer may be provided.

By providing this oxygen concentration regulating means, the oxygenconcentration in the hermetic container is regulated independently oftotal pressure. The degree of freedom of treatment in the hermeticcontainer is raised by regulating the oxygen concentration in thehermetic container. For example, the resins can be thermally decomposedselectively without the thermal conductivity inside the first hermeticzone being lowered. In addition, the oxidation and vaporization of thecomponent metals of the object to be treated can be suppressed.Specially when the object to be treated contains resins as itscomponent, the resins can be thermally decomposed selectively moreeffectively while the state of lead is substantially maintained byregulating the oxygen concentration in the hermetic container. Theresins can be thermally decomposed selectively more positively, forexample, by pressurizing the interior of the hermetic container in anon-oxidizing atmosphere to about one atmosphere to about tenatmospheres.

As the oxygen concentration regulating means, for example, an oxygenconcentration sensor which is an oxygen concentration measuring meansand a carrier gas introduction system may be used.

As the oxygen concentration sensor, for example, a so-called zirconiasensor using zirconia (zirconium oxide) may be used, or the absorptionof CO and CO₂, for example, may be measured by infrared spectroscopy.Besides, GC-MS may be used. It is suitable that the oxygen concentrationsensor is selected from them as required or they are used incombination.

The treatment system includes a control means for controlling theaforesaid temperature regulating means and pressure regulating means oroxygen concentration regulating means. This control means controls thetemperature and pressure or oxygen concentration in the hermeticcontainer so that resins are thermally decomposed selectively and sothat lead in the object to be treated is vaporized selectively. It issuitable that this control means measures the state inside the hermeticcontainer by the aforesaid temperature sensor, pressure sensor, oxygenconcentration sensor, and the like and feeds back the measured values tothe heating means, the exhaust system, the pressurization system, thecarrier gas introduction system, and the like to optimize the stateinside the hermetic container.

Such control may be performed by an operator's operating the heatingmeans, the exhaust system, the pressurization system, and the carriergas introduction system according to a parameter of the state inside thehermetic container.

Moreover, a control device, in which the measured parameter of the stateinside the hermetic container is an input and a signal for operating theheating means, the exhaust system, the pressurization system, and thecarrier gas introduction system so that conditions in the hermeticcontainer are optimized is an output, may be provided. This controlcircuit may be stored as a program in a memory means of the controldevice.

According to another aspect, a first step in a treatment method is astep of heating an object to be treated to thermally decompose resinsselectively.

Resins such as plastic and the like start melting at about 323K (50°C.), and they are thermally decomposed at about 453K to 873K (180° C. to600° C.) and mainly emits hydrocarbon gases of C1 to C16. These gasesproduced by selective thermal decomposition of resins can be recoveredas valuable oil, for example, by being condensed by the exhaust gastreatment system or the like.

It is desirable to perform the selective thermal decomposition of resinsin the container where the oxygen concentration is regulated. The oxygenconcentration may be regulated by the total pressure in the hermeticcontainer, or may be regulated by the introduction of a carrier gas suchas N₂ or Ar.

The oxidation of lead can be prevented by regulating the oxygenconcentration in the hermetic container. Moreover, the oxidation of leadcan be prevented without the thermal conductivity inside the hermeticcontainer being lowered by regulating the oxygen concentrationseparately from the total pressure, thereby improving the decompositionefficiency of resins and the recovery efficiency of gases produced bydecomposition. Depending on the situation, it is suitable to increasethe pressure in the hermetic container by introducing a carrier gas suchas N₂ or Ar to thereby thermally decompose resins selectively.

Resins in the object to be treated do not need to be thermallydecomposed completely but only need to be decomposed to such a degreethat a bad influence is not exerted on the separation and recovery oflead.

Lead (metal) shows a vapor pressure of 760 mmHg at 2017K, whereas leadoxide shows a vapor pressure of 760 mmHg at 1745K which is lower.Accordingly, the regulation of the oxygen concentration in the hermeticcontainer can inhibit metallic lead from being oxidized into lead oxide,leading to prevention of scattering of lead, and thus lead can berecovered more positively in the subsequent process.

After the resins in the object to be treated are thermally decomposedselectively as described above, the temperature and pressure in thehermetic container are controlled so that lead is vaporized selectively,and the lead is separated and recovered from the object to be treated.

When metals other than lead are contained in the object to be treated,lead is vaporized selectively by a difference in vapor pressure.

The temperature at which lead is vaporized changes depending on thepressure in the hermetic container. Under atmospheric pressure, thevapor pressure of lead when being heated to 1673K is 84 mmHg, whereasthe vapor pressure of iron, copper, or tin does not reach even 1 mmHg.

Therefore, almost only lead vapor can be generated selectively from theobject to be treated by heating the object to be treated to about 1673K.

Further, under atmospheric pressure, the vapor pressure of lead whenbeing heated to 2013K is 760 mmHg, whereas the vapor pressure of tindoes not reach even 15 mmHg and the vapor pressure of copper does notreach even 3 mmHg. Therefore, almost only lead vapor can be generatedselectively from the object to be treated by heating the object to betreated to about 1673K.

Furthermore, lead in the object to be treated can be vaporized at alower temperature by reducing the pressure in the hermetic container.

If the pressure in the hermetic container is regulated at 10⁻¹ Torr,almost only lead vapor can be generated selectively from the object tobe treated by heating the object to be treated to about 1100K.

Further, if the pressure in the hermetic container is regulated at 10⁻³Torr, almost only lead vapor can be generated selectively from theobject to be treated by heating the object to be treated to about 900K.

Furthermore, if the pressure in the hermetic container is regulated at10⁻⁴ Torr, almost only lead vapor can be generated selectively from theobject to be treated by heating the object to be treated to about 700K.

The lead vapor generated selectively as described above is recovered asmetallic lead by a recovery device or the like which is cooled to themelting point of lead or lower.

When the vaporized lead is recovered after being condensed andcrystallized, the recovery percentage of lead is raised by setting theretention time of vaporized lead in the device for a long time. Forexample, the recovery device may have counter-current structure orhelical structure.

Moreover, the lead vapor can be recovered more selectively by letting arare gas such as N₂ or Ar as a carrier gas flow into the recovery devicefrom within the hermetic container.

By continuously performing the step of thermally decomposing resinsselectively and the step of vaporizing lead selectively, energy to besupplied in the subsequent step can be greatly held down.

Namely, the thermal conductivity of a gas lowers with a drop inpressure, and hence the supply of larger energy is required as thepressure in the hermetic container is reduced in the step of vaporizinglead. In the treatment system and treatment method, however, the step ofthermally decomposing resins is also a preheating stage of the step ofvaporizing lead, and thus energy to be supplied in the step ofvaporizing lead can be greatly saved.

Moreover, moisture and oil in the object to be treated are removed fromthe object to be treated in the thermal decomposition step of resins,and thus a bad influence is never exerted on the step of vaporizinglead.

According to another aspect, provided is a treatment system for treatingan object to be treated having a first object and a second object whichare bonded by a metal, including a hermetic container for holding theobject to be treated therein, a temperature regulating means forregulating the temperature in the hermetic container, a pressureregulating means for regulating the pressure in the hermetic container,and a control means for controlling the temperature regulating means andthe pressure regulating means so that the metal bonding the first objectand the second object is vaporized.

Further, it may include a hermetic container for holding a first objectand a second object which are bonded by an alloy having a first metaland a second metal therein, a temperature regulating means forregulating the temperature in the hermetic container, a pressureregulating means for regulating the pressure in the hermetic container,and a control means for controlling the temperature regulating means andthe pressure regulating means so that the temperature and pressure inthe hermetic container are regulated such that the alloy is vaporized.

Furthermore, it may include a hermetic container for holding a firstobject and a second object which are bonded by an alloy composed of afirst metal and a second metal and have resins as their componentstherein, a temperature regulating means for regulating the temperaturein the hermetic container, a pressure regulating means for regulatingthe pressure in the hermetic container, a first control means forcontrolling the temperature regulating means so that the resins arethermally decomposed selectively, a second control means for controllingthe temperature regulating means and the pressure regulating means sothat the temperature and pressure in the hermetic container areregulated such that the first metal of the alloy is vaporizedselectively, a third control means for controlling the temperatureregulating means and the pressure regulating means so that thetemperature and pressure in the hermetic container are regulated suchthat the second metal of the alloy is vaporized, a first recovery meansfor recovering gases produced by the selective thermal decomposition ofthe resins, and a second recovery means for recovering the first metalvaporized from the alloy. Moreover, the resins may be thermallydecomposed selectively while the oxidation states of the first andsecond metals are substantially maintained.

Additionally, it may include a hermetic container for holding a firstobject and a second object which are bonded by an alloy composed of afirst metal and a second metal and have resins as their componentstherein, a temperature regulating means for regulating the temperaturein the hermetic container, a pressure regulating means for regulatingthe pressure in the hermetic container, a first control means forcontrolling the temperature regulating means so that the temperature andpressure in the hermetic container are regulated such that the resinsare thermally decomposed selectively, a second control means forcontrolling the temperature regulating means and the pressure regulatingmeans so that the temperature and pressure in the hermetic container areregulated such that the first metal of the alloy is vaporizedselectively, a third control means for controlling the temperatureregulating means and the pressure regulating means so that thetemperature and pressure in the hermetic container are regulated suchthat the second metal of the alloy is vaporized, a first recovery meansfor recovering gases produced by the selective thermal decomposition ofthe resins, and a second recovery means for recovering the first metalvaporized from the alloy. Moreover, the resins may be thermallydecomposed selectively while the oxidation states of the first andsecond metals are substantially maintained.

According to another aspect, provided is a treatment system for treatingan object to be treated having a first object and a second object whichare bonded by an alloy having a first metal and a second metal and haveresins as their components, including a hermetic container for holdingthe object to be treated therein, a temperature regulating means forregulating the temperature in the hermetic container, a pressureregulating means for regulating the pressure in the hermetic container,an oxygen concentration regulating means for regulating the oxygenconcentration in the hermetic container, a first control means forcontrolling the temperature regulating means and the oxygenconcentration regulating means so that the resins are thermallydecomposed selectively, a second control means for controlling thetemperature regulating means and the pressure regulating means so thatthe first metal of the alloy is vaporized selectively, a third controlmeans for controlling the temperature regulating means and the pressureregulating means so that the second metal of the alloy is vaporized, afirst recovery means for recovering gases produced by the selectivethermal decomposition of the resins, and a second recovery means forrecovering the first metal vaporized from the alloy.

Moreover, the first control means may control the temperature regulatingmeans and the oxygen concentration regulating means so that thetemperature and oxygen concentration in the hermetic container areregulated such that the resins are thermally decomposed selectivelywhile the first metal of the alloy is maintained so as not to besubstantially oxidized.

At least one element out of Zn, Cd, Hg, Ga, In, Tl, Sn, Pb, Sb, Bi, Ag,or In as the first metal may be separated or recovered from the objectto be treated.

Further, by regulating the temperature, pressure, oxygen concentrationin the hermetic container, metals other than these can be separated andrecovered in a metallic state (See FIG. 30). This point applies to allportions of the description even when not specially described.

According to another aspect, provided is a treatment method for treatingan object to be treated having a first metal and a second metal whichare bonded by a metal, including introducing the object to be treatedinto a hermetic container and hermetically sealing this hermeticcontainer, and regulating the temperature and pressure in the hermeticcontainer so that the metal is vaporized.

Further, it may include introducing a first object and a second objectwhich are bonded by an alloy having a first metal and a second metalinto a hermetic container and hermetically sealing this hermeticcontainer, and regulating the temperature and pressure in the hermeticcontainer so that the alloy is vaporized.

Furthermore, it may include introducing an object to be treated having afirst object and a second object which are bonded by an alloy having afirst metal and a second metal and have resins as their components intoa hermetic container and hermetically sealing this hermetic container, afirst step of regulating the temperature and pressure in the hermeticcontainer so that the resins are thermally decomposed selectively, asecond step of regulating the temperature and pressure in the hermeticcontainer so that the first metal in the alloy is vaporized selectively,a third step of regulating the temperature and pressure in the hermeticcontainer so that the second metal in the alloy is vaporized, a firstrecovery step of recovering gases produced by the decomposition of theresins, and a second recovery step of recovering the first metalvaporized from the alloy.

In the first step, the temperature and pressure in the hermeticcontainer may be regulated so that the resins are thermally decomposedselectively while the state of the first metal in the alloy issubstantially maintained.

According to another aspect, provided is a treatment method for treatingan object to be treated having a first object and a second object whichare bonded by an alloy having a first metal and a second metal and haveresins as their components, including introducing the object to betreated into a hermetic container and hermetically sealing this hermeticcontainer, a first control step of regulating the temperature and oxygenconcentration in the hermetic container so that the resins are thermallydecomposed selectively, a second control step of regulating thetemperature and pressure in the hermetic container so that the firstmetal in the alloy is vaporized selectively, a third control step ofregulating the temperature and pressure in the hermetic container sothat the second metal in the alloy is vaporized, a first recovery stepof recovering gases produced by the thermal decomposition of the resins,and a second recovery step of recovering the first metal vaporized fromthe alloy.

In the first control step, the temperature and oxygen concentration inthe hermetic container may be regulated so that the resins are thermallydecomposed selectively while the first and the second metals in thealloy are maintained so as not to substantially oxidized.

Furthermore, it includes introducing a mounting substrate composed of acircuit board having resins as its component and electronic parts bondedto this circuit board by an alloy having a first metal and a secondmetal into a hermetic container and hermetically sealing this hermeticcontainer, a first control step of regulating the temperature and oxygenconcentration in the hermetic container so that the resins are thermallydecomposed selectively, a second control step of regulating thetemperature and pressure in the hermetic container so that the firstmetal in the alloy is vaporized selectively, a third control step ofregulating the temperature and pressure in the hermetic container sothat the second metal in the alloy is vaporized, a first recovery stepof recovering gases produced by the selective thermal decomposition ofthe resins, and a second recovery step of recovering the first metalvaporized from the alloy. In the first control step, the temperature andoxygen concentration in the hermetic container may be regulated so thatthe resins are thermally decomposed selectively while the states of thefirst and second metals in the alloy are substantially maintained.

The treatment system of the aforesaid aspect can release bonding of theobject to be treated in which the bonding is performed by a metal or analloy. Moreover, the treatment method can release bonding of the objectto be treated in which the bonding is performed by a metal or an alloy.

A basic idea of the aforesaid treatment system and treatment method isto introduce an object to be treated into a hermetic container, regulatethe temperature, pressure, oxygen concentration, and the like in thehermetic container to vaporize a bonding metal or alloy, and thereby torelease bonding. The vaporized metal can be recovered, for example, bybeing condensed.

When the object to be treated has resins as its component, resinousportions are first thermally decomposed selectively, and gasified,liquefied, or carbonized. This selective thermal decomposition of theresins may be performed while the temperature, pressure, or oxygenconcentration in the hermetic container is regulated on such a conditionthat metal is not oxidized nor vaporized much. Namely, the resins may bethermally decomposed while an oxidation state and a phase equilibriumstate of the component metals of the object to be treated are maintainedas constant as possible.

Subsequently, the temperature and pressure in the hermetic container areregulated to vaporize the bonding metal in the object to be treatedselectively. When a plurality of metals (elements) are contained in theobject to be treated, it is recommended that the temperature andpressure in the hermetic container be regulated according to respectivemetals to thereby vaporize each of the metals selectively.

The treatment apparatus of the aforesaid aspect may be used for atreatment apparatus portion of the treatment system. Namely, forexample, selective thermal decomposition of resins and vaporization oflead may be performed by regulating conditions such as temperature,pressure, and oxygen concentration in one hermetic container stepwise.Moreover, selective thermal decomposition of resins and vaporization oflead may be performed by providing a plurality of hermetic zonesdifferent in conditions such as temperature, pressure, and oxygenconcentration and opening and closing partitions which partitionrespective hermetic zones to transfer the object to be treatedsequentially.

Moreover, the temperature regulating means, the pressure regulatingmeans, the oxygen concentration regulating means, the control means, theresin recovering means, metal recovery means, and the like are the sameas described above.

As for the object to be treated of the treatment system and treatmentmethod, a mounting substrate in which a print-circuit board and variouskinds of electronic parts are bonded by a solder alloy such as Pb—Sn andelectronic equipment having such a mounting substrate can be given asexamples.

In addition to the mounting substrate, for any object to be treated inwhich bonding is performed by a metal or alloy, the bonding can bereleased.

It is suitable, for example, to introduce a mounting substrate to thetreatment apparatus, heat the mounting substrate to a temperature (forexample, about 473K) such that resins are not oxidized much whileregulating the oxygen concentration, reduce the pressure in the hermeticcontainer, regulate the oxygen concentration, further heat the mountingsubstrate to a temperature (for example, about 523K to about 773K at10⁻³ Torr) such that lead is not oxidized nor vaporized to thermallydecompose component resins of the mounting substrate, then heat themounting substrate to the boiling point of lead (for example, about 900Kat 10⁻³ Torr) or higher to vaporize lead and similarly vaporize tin tothereby separate the mounting substrate into electronic parts and acircuit board (A board on which the electronic parts are mounted iscalled here a circuit board.), and recover them.

For the vaporization of metals such as lead on the occasion of selectivethermal decomposition of resins, the provision of a metal separatingmeans in the recovery system is recommended. This respect is common toall the description.

Further, it is suitable, for example, to introduce a mounting substrateto the treatment apparatus, heat the mounting substrate to a temperature(for example, about 473K) such that resins are not oxidized so muchwhile regulating the oxygen concentration, reduce the pressure in thehermetic container, regulate the oxygen concentration, further heat themounting substrate to a temperature (for example, about 523K to about773K at 10 ⁻³ Torr) such that lead is not substantially oxidized norvaporized to thermally decompose component resins of the mountingsubstrate, then heat the mounting substrate, for example, to about 973Kto vaporize Zn, Sb, and the like, and recover them.

Furthermore, it is suitable to heat the mounting substrate, for example,to about 1773K to thereby vaporize Au, Pt, Pd, Ta, Ni, Cr, Cu, Al, Co,W, Mo, and the like and recover them.

A solder alloy is not limited to PB—Sn, and so-called Pb-free soldersuch as Ag—Sn, Zn—Sn, In—Sn, Bi—Sn, Sn—Ag—Bi, or Sn—Ag—Bi—Cu is alsosuitable. Bonding by alloys other than these or a simple metal is alsosuitable.

The object to be treated may contain resins as its component. The resinsmay be thermoplastic resins, thermoset resins, or a mixture of theseresins.

When the object to be treated contains resins as its component, as hasbeen described so far, it is recommended that resinous portions bethermally decomposed (vaporized, liquefied, carbonized, or the like)selectively. Gases produced by the selective thermal decomposition maybe condensed by the exhaust gas treatment system, for example, andrecovered. Recovered decomposition products of resins such as light oiland heavy oil may be used for heating the object to be treated. It isunnecessary to completely perform the selective thermal decomposition ofresin components, and it is desirable to thermally decompose them to theextent that the separation and recovery of the bonding metal are notdisturbed. Also, as described above, for the vaporization of a part ofthe bonding metal, the provision of a separating means for the vaporizedmetal in the recovery system is recommended.

Resins such as plastic and the like start melting at about 323K, andthey are thermally decomposed at about 453K to 873K and mainly emitshydrocarbon gases of C1 to C8 and C8 to C16. These gases produced byselective thermal decomposition of resins can be recovered as valuableoil, for example, by being condensed by the exhaust gas treatment systemor the like. Generally, most of resins composing the circuit board arethermoset resins, and most of their components are carbonized orvaporized.

It is desirable to perform the selective thermal decomposition of resinsin the container where the oxygen concentration is regulated. The oxygenconcentration may be regulated by the total pressure in the hermeticcontainer, or may be regulated by the introduction of a carrier gas suchas N₂ or Ar.

The oxidation of a bonding metal such as lead or tin can be prevented byregulating the oxygen concentration in the hermetic container. Moreover,the oxidation of the metal can be prevented without the thermalconductivity inside the hermetic container being lowered by regulatingthe oxygen concentration separately from the total pressure, therebyimproving the decomposition efficiency of resins and the recoveryefficiency of gases produced by decomposition. Depending on thesituation, it is suitable to increase the pressure in the hermeticcontainer by introducing a carrier gas such as N₂ or Ar to therebythermally decompose resins selectively. The resins in the object to betreated do not need to be thermally decomposed completely but only needto be decomposed to such a degree that a bad influence is not exerted onthe separation and recovery of the metal.

For example, metallic lead shows a vapor pressure of 760 mmHg at 2017K,whereas lead oxide shows a vapor pressure of 760 mmHg at 1745K.Accordingly, the regulation of the oxygen concentration in the hermeticcontainer can inhibit the metal from being oxidized into lead oxide, andthus the metal can be recovered more positively in the subsequentprocess. In addition, utility value is raised by recovering it as metal.After the resins are thermally decomposed while the state of lead in theobject to be treated is substantially maintained as described above, thetemperature and pressure in the hermetic container are controlled sothat lead is vaporized selectively, and the lead is separated andrecovered from the object to be treated.

Even when metals other than lead are contained in the object to betreated, lead is vaporized selectively by a difference in vaporpressure.

For example, the temperature at which lead is vaporized changesdepending on the pressure in the hermetic container. Under atmosphericpressure, the vapor pressure of lead when being heated to, for example,1673K is 84 mmHg, whereas the vapor pressure of iron, copper, or tindoes not reach even 1 mmHg. Therefore, almost only lead vapor can begenerated selectively from the object to be treated by heating theobject to be treated to about 1673K.

Further, under atmospheric pressure, the vapor pressure of lead whenbeing heated to, for example, 2013K is 760 mmHg, whereas the vaporpressure of tin does not reach even 15 mmHg and the vapor pressure ofcopper does not reach even 3 mmHg. Therefore, almost only lead vapor canbe generated selectively from the object to be treated by heating theobject to be treated to about 1673K.

Furthermore, lead in the object to be treated can be vaporized at alower temperature by reducing the pressure in the hermetic container.

If the pressure in the hermetic container is regulated at 10⁻¹ Torr,almost only lead vapor can be generated selectively from the object tobe treated by heating the object to be treated to about 1100K.

Further, if the pressure in the hermetic container is regulated at 10⁻³Torr, almost only lead vapor can be generated selectively from theobject to be treated by heating the object to be treated to about 900K.

Furthermore, if the pressure in the hermetic container is regulated at10⁻⁴ Torr, almost only lead vapor can be generated selectively from theobject to be treated by heating the object to be treated to about 700K.

The lead vapor generated selectively as above is recovered as metalliclead by a recovery device which is cooled to the melting point of leador lower or the like.

When the vaporized lead is recovered after being condensed andcrystallized as above, the recovery percentage of lead is raised bysetting the retention time of vaporized lead in the device for a longtime. For example, the recovery device may have counter-currentstructure or helical structure.

Moreover, the lead vapor can be recovered more selectively by letting arare gas such as N₂ or Ar as a carrier gas flow into the recovery devicefrom within the hermetic container.

By continuously performing the step of thermally decomposing resins andthe step of vaporizing lead selectively, energy to be supplied in thesubsequent step can be greatly held down.

Namely, the thermal conductivity of a gas lowers with a drop inpressure, and hence the supply of larger energy is required as thepressure in the hermetic container is reduced in the step of vaporizinglead. In the treatment system and treatment method, however, the step ofthermally decomposing resins is also a preheating stage of the step ofvaporizing lead, and thus energy to be supplied in the step ofvaporizing lead can be saved greatly.

Moreover, moisture and oil in the object to be treated are removed fromthe object to be treated in the thermal decomposition step of resins,and thus a bad influence is never exerted on the step of vaporizinglead.

According to another aspect, provided is a treatment system for treatingan object to be treated in which resins and metals are integrated,including a hermetic container for holding the object to be treatedtherein, a temperature regulating means for regulating the temperaturein the hermetic container, a pressure regulating means for regulatingthe pressure in the hermetic container, and a control means forcontrolling the temperature regulating means and the pressure regulatingmeans in the hermetic container so that the resins are thermallydecomposed selectively.

The control means for controlling the temperature regulating means andthe pressure regulating means may control the temperature regulatingmeans and the pressure regulating means in the hermetic container sothat the resins are thermally decomposed selectively while the state ofmetals is substantially maintained.

According to another aspect, a treatment system may include a hermeticcontainer for holding an object to be treated in which resins and metalsare integrated therein, a temperature regulating means for regulatingthe temperature in the hermetic container, an oxygen concentrationregulating means for regulating the oxygen concentration in the hermeticcontainer, and a control means for controlling the temperatureregulating means and the oxygen concentration regulating means so thatthe resins are thermally decomposed selectively while the state ofmetals is substantially maintained. On the occasion of the selectivethermal decomposition of resins, the temperature, pressure or oxygenconcentration may be regulated so that the state of component metals aremaintained as constant as possible.

According to another aspect, provided is a treatment system for treatingan object to be treated in which resins and metals are integrated,including a hermetic container for holding the object to be treatedtherein, a temperature regulating means for regulating the temperaturein the hermetic container, a pressure regulating means for regulatingthe pressure in the hermetic container, an oxygen concentrationregulating means for regulating the oxygen concentration in the hermeticcontainer, and a control means for controlling the temperatureregulating means, the pressure regulating means, and the oxygenconcentration regulating means in the hermetic container so that theresins are thermally decomposed selectively.

Moreover, the control means may control the temperature regulatingmeans, the pressure regulating means and the oxygen concentrationregulating means in the hermetic container so that the resins arethermally decomposed selectively while the state of metals issubstantially maintained.

According to another aspect, a treatment system may include a hermeticcontainer for holding an object to be treated in which resins, a firstmetal, and a second metal are integrated therein, a temperatureregulating means for regulating the temperature in the hermeticcontainer, a pressure regulating means for regulating the pressure inthe hermetic container, an oxygen concentration regulating means forregulating the oxygen concentration in the hermetic container, and acontrol means for controlling the temperature regulating means and theoxygen concentration regulating means so that the resins are thermallydecomposed selectively, a second control means for controlling thetemperature regulating means and the pressure regulating means so thatthe first metal is vaporized selectively, and a recovery means forrecovering the first metal vaporized from the object to be treated. Thecontrol means may control the temperature regulating means and theoxygen concentration means in the hermetic container so that the resinsare thermally decomposed selectively while the state of the first andsecond metals is substantially maintained.

According to another aspect, a treatment method includes introducing anobject to be treated in which resins and metals are integrated to ahermetic container, and regulating the temperature and oxygenconcentration in the hermetic container so that the resins are thermallydecomposed selectively.

The temperature and oxygen concentration in the hermetic container maybe regulated so that the resins are thermally decomposed selectivelywhile the state of metals is substantially maintained. According toanother aspect, a treatment system may include introducing an object tobe treated in which resins and metals are integrated to a hermeticcontainer, and regulating the temperature and pressure in the hermeticcontainer so that the resins are thermally decomposed selectively.

According to another aspect, a treatment method includes introducing anobject to be treated in which resins and metals are laminated to ahermetic container, regulating the temperature and oxygen concentrationin the hermetic container so that the resins are thermally decomposedselectively, and regulating the temperature and pressure in the hermeticcontainer so that the surface area of the object to be treated decreasesas the metals melt.

The temperature and oxygen concentration in the hermetic container maybe regulated so that the resins are thermally decomposed while themetals are maintained not so as to be substantially oxidized.

According to another aspect, a treatment method may include introducingan object to be treated in which resins and copper are laminated to ahermetic container, regulating the temperature and oxygen concentrationin the hermetic container so that the resins are thermally decomposedselectively while the state of the copper is substantially maintained,and regulating the temperature and pressure in the hermetic container sothat the surface area of the object to be treated decreases as thecopper melts.

According to another aspect, a treatment method may include introducingan object to be treated in which resins and metals are integrated to ahermetic container, and regulating the temperature, pressure, and oxygenconcentration in the hermetic container so that the resins are thermallydecomposed selectively while the state of the metals is substantiallymaintained.

According to another aspect, a treatment method includes introducing anobject to be treated in which resins, a first metal and a second metalare integrated to a hermetic container, and a first control step ofregulating the temperature and oxygen concentration in the hermeticcontainer so that the resins are thermally decomposed selectively, asecond control step for regulating the temperature and pressure in thehermetic container so that the first metal is vaporized selectively, anda step of recovering the first metal vaporized from the object to betreated.

Furthermore, in the first control step, the temperature and oxygenconcentration in the hermetic container may be regulated so that theresins are thermally decomposed selectively while the first and secondmetals are maintained so as not to be substantially oxidized.

The treatment system is a system capable of treating an object to betreated having resins and metals as its components.

Further, the treatment method is a method capable of treating an objectto be treated having resins and metals as its components.

Namely, a basic idea of the treatment system and the treatment method isto introduce an object to be treated having resins and metals as itscomponents to a hermetic container, first thermally decompose resinousportions selectively, and thereby vaporize, liquefy, or carbonize them.This selective thermal decomposition of resins may be performed byregulating the temperature, pressure or oxygen concentration in thehermetic container on such a condition that the metals are not oxidizednor vaporized.

When it is still difficult to separate the metals from the object to betreated by this operation only, the temperature and pressure in thehermetic container are then regulated to thereby vaporize the metals inthe object to be treated selectively. When a plurality of metals(elements) are contained in the object to be treated, the temperatureand pressure in the hermetic container are regulated depending onrespective metals to thereby vaporize each of the metals selectively. Asfor the apparatus, for example, the treatment apparatus as describedabove may be used.

The object to be treated of such a treatment system or treatment methodis not only an object to be treated having resins and metals but also anobject to be treated in which resins and metals are integrated.

As an example of the object to be treated having resins and metals,aluminum foil laminated by a plastic film in packing receptacles forretort pouch food, a syringe, a print-circuit board in which resins andmetals such as copper and nickel are integrated, a flexible board or afilm carrier of TAB, an IC, an LSI, or a resistor can be given. Inaddition, wastes from which lead is removed by means of the treatmentsystem or the treatment method may be an object to be treated.

Moreover, the object to be treated in which bonding by a metal or analloy is released by means of the treatment system or the treatmentmethod may be an object to be treated. For example, a mounting substrateis separated into a substrate and electronic parts by means of thetreatment system and the treatment method, and the substrate and theparts may be objects to be treated respectively. Further, respectiveaspects of the treatment apparatus, the treatment system, or thetreatment method may be combined, for example.

In order to thermally decompose organic substances in the object to betreated, or in order to thermally decompose organic substances whilemaintaining component metals so as to be oxidized or vaporized as littleas possible, for example, the object to be treated may be heated whilethe pressure in the hermetic container is controlled, or the object tobe treated may be heated while the oxygen concentration in the hermeticcontainer is controlled.

To control the oxygen concentration, oxygen partial pressure may beregulated by regulating the total pressure in the hermetic container, orthe oxygen concentration in the system may be regulated by introducing agas such as nitrogen gas or a rare gas into the hermetic container. Ifthe oxidation of resinous portions progresses rapidly by heating theobject to be treated, that is, the resinous portions are combusted,metallic portions which are integrated with the resinous portions arealso oxidized into oxides, which lowers their utility value, and thusattention is required.

In heating the object to be treated, thermal conductivity is lowered andtemperature regulating efficiency is lowered if the pressure in thehermetic container is reduced. Thus, it is suitable to reduce thepressure after heating the resins to a predetermined temperature, andthen heat further the object to be treated.

Moreover, it is suitable to raise thermal conductivity by heating theinterior of the hermetic container under pressure to a temperature suchthat the oxidation state of metals is maintained in a non-oxidizingatmosphere to thereby raise temperature increase efficiency, reduce thepressure after heating the object to be treated to the temperature suchthat the oxidation state is maintained, and then heat it further. Therecovery percentage of decomposed components of resins with relativelysmall molecular weight is elevated by heating under pressure.

When metallic portions are composed of a plurality of metals, it issuitable to heat further the object to be treated to thereby vaporizerespective metals selectively and recover each of the metals.

Gases produced by decomposition of resins of the object to be treatedmay be recovered by being condensed, and may be recovered, for example,by the exhaust gas system. Moreover, they may be condensed after beingreformed and thermally decomposed, for example, at a temperature of1000° C. or higher. The production of dioxins can be suppressed bycooling from a high temperature of 1000° C. of higher to normaltemperature.

It is recommended to recover hydrogen gas by being adsorbed, and whenhalogenated hydrocarbon or the like is produced, it may be decomposed bya catalyst or the like.

When resins are polyvinyl chloride resin and the like which containhalogen, first, wastes may be heated to normal temperature in a range inwhich the oxidation state of component metals of the wastes aremaintained to produce halogen gas. The produced halogen gas may bebrought into contact with iron heated to a high temperature andrecovered as iron halide, or may be reacted with ammonium and recoveredas ammonium halide.

These gases produced by the heating of wastes may be treated by means ofa multi-gas treatment system.

As an example of treatment, for example, concerning the treatment ofaluminum foil laminated by a plastic film (hereinafter referred to asresin-coated aluminum foil) used for various kinds of packingreceptacles, the thermal decomposition such as carbonization orliquefaction of resinous portions is insufficient in the case oftemperatures below 673K. Moreover, since aluminum melts if it is heatedto 923K or higher, and thus the resinous portions are thermallydecomposed (vaporized, liquefied, or carbonized) selectively by heatingit in the range of 673K to 923K, and aluminum foil is recovered in ametallic state.

It is more preferable that the pressure in the hermetic container isreduced to about 10⁻² Torr or lower or the oxygen concentration isregulated by introducing gas such as N₂ or Ar and that heating is thenperformed. It is more preferable to set the heating temperature at 823 Kto 873K.

According to another aspect, a wastes treatment system includes ahermetic container for holding wastes in which resins and copper areintegrated therein, a temperature regulating means for regulating thetemperature in the hermetic container, and a control means forcontrolling the temperature in the hermetic container so that the resinsare thermally decomposed selectively while the copper is notsubstantially oxidized.

According to another aspect, a wastes treatment system includes ahermetic container for holding wastes in which resins and copper areintegrated therein, a temperature regulating means for regulating thetemperature in the hermetic container, an oxygen concentrationregulating means for regulating the oxygen concentration in the hermeticcontainer, and a control means for controlling the temperature andoxygen concentration in the hermetic container so that the resins arethermally decomposed selectively while the copper is maintained so asnot to be substantially oxidized.

In the case of temperatures below 673K, the thermal decomposition suchas carbonization or liquefaction of resinous portions is insufficient.It is possible to vaporize, liquefy, or carbonize the resins and torecover the copper in a metallic state as it is by heating the wastes inthe range of 673K to 923K.

It is more preferable that the pressure in the hermetic container isreduced to about 10⁻² Torr or lower or the oxygen concentration isregulated by introducing gas such as N₂ or Ar and that heating is thenperformed. It is more preferable to set the heating temperature at 823 Kto 873K.

Further, there is a need to provide a treatment apparatus and atreatment method for treating an object such as shredder dust containingmetals and resins while suppressing the production of dioxins.

Furthermore, there is a need to provide a treatment apparatus and atreatment method for separating an object such as a circuit board onwhich electronic parts and the like are mounted into the electronicparts and the circuit board while suppressing the production of dioxins,separating and recovering noxious metals such as lead and the like andmetals such as copper and the like.

To address such problems, according to another aspect, a treatmentapparatus includes a first thermal decomposition means for thermallydecomposing an object containing resins and metals at a firsttemperature, a reforming means, connected to the thermal decompositionmeans, for reforming a gaseous emission produced from the object at asecond temperature such that dioxins are decomposed, a cooling means,connected to the reforming means, for cooling the gaseous emission to athird temperature so that a rise in the concentration of dioxins in thegaseous emission reformed at the second temperature is suppressed, areduced pressure heating means for heating a residue produced by thethermal decomposition of the object under reduced pressure so that ametal contained in this residue is vaporized, and a condensing means forcondensing the metal vaporized from the residue.

According to another aspect, a treatment apparatus includes a firstthermal decomposition means for thermally decomposing an objectcontaining resins and metals at a first temperature, a second thermaldecomposition means, connected to the thermal decomposition means, forthermally decomposing a gaseous emission produced from the object at asecond temperature higher than the first temperature, a cooling means,connected to the thermal decomposition means, for cooling the gaseousemission to a third temperature so that a rise in the concentration ofdioxins in the gaseous emission which is thermally decomposed at thesecond temperature is suppressed, a reduced pressure heating means forheating a residue produced by the thermal decomposition of the objectunder reduced pressure so that a metal contained in this residue isvaporized, and a condensing means for condensing the metal vaporizedfrom the residue.

According to another aspect, a treatment apparatus may include a firstthermal decomposition means for thermally decomposing an objectcontaining resins, a first metal, and a second metal at a firsttemperature, a reforming means, connected to the first thermaldecomposition means, for reforming a gaseous emission produced from theobject at a second temperature such that dioxins are decomposed, acooling means, connected to the reforming means, for cooling the gaseousemission to a third temperature so that a rise in the concentration ofdioxins in the gaseous emission reformed at the second temperature issuppressed, a first reduced pressure heating means for heating a residueproduced by the thermal decomposition of the object under reducedpressure so that the first metal contained in this residue is vaporizedand the second metal is maintained, a condensing means, connected to thefirst reduced pressure heating means, for condensing the first metalvaporized from the residue, and a second reduced pressure heating meansfor heating the residue under reduced pressure so that the second metalcontained in the residue from which the first metal is vaporized melts.

The second reduced pressure heating means of the treatment apparatus mayheat the residue under reduced pressure so that the second metalcontained in the residue from which the first metal is vaporized meltsand it coheres by its surface tension.

According to another aspect, a treatment apparatus may include a thermaldecomposition means for thermally decomposing an object having resinsand metals as a part of its components and having a first portion and asecond portion which are bonded by a bonding metal while maintaining thebonding metal, a reforming means, connected to the thermal decompositionmeans, for reforming a gaseous emission produced from the object at asecond temperature such that dioxins are decomposed, a cooling means,connected to the reforming means, for cooling the gaseous emission to athird temperature so that a rise in the concentration of dioxins in thereformed gaseous emission is suppressed, and a reduced pressure heatingmeans for heating a residue produced by the thermal decomposition of theobject under reduced pressure so that the bonding metal is vaporized.

It is recommended that such a thermal decomposition means of thetreatment apparatus perform thermal decomposition in a non-oxidationatmosphere or a reducing atmosphere by controlling oxygen concentrationor the like. Moreover, it is recommended that the cooling means performcooling to the third temperature in the shortest possible time, and morepreferably within about ten seconds.

Moreover, the treatment apparatus may further include a neutralizingmeans, connected to the cooling means, for neutralizing the cooledgaseous emission.

According to another aspect, a treatment method includes a first thermaldecomposition step of thermally decomposing an object containing resinsand metals at a first temperature, a reforming step of reforming agaseous emission produced from the object at a second temperature suchthat dioxins are decomposed, a cooling step of cooling the gaseousemission to a third temperature so that a rise in the concentration ofdioxins in the reformed gaseous emission is suppressed, a reducedpressure heating step of heating a residue produced by the thermaldecomposition of the object under reduced pressure so that a metalcontained in this residue is vaporized, and a condensing step ofcondensing the metal vaporized from the residue.

According to another aspect, a treatment method includes a first thermaldecomposition step of thermally decomposing an object containing resinsand metals at a first temperature, a second thermal decomposition stepof thermally decomposing a gaseous emission produced from the object ata second temperature higher than the first temperature, a cooling stepof cooling the gaseous emission to a third temperature so that a rise inthe concentration of dioxins in the gaseous emission which is thermallydecomposed at the second temperature is suppressed, a reduced pressureheating means for heating a residue produced by the thermaldecomposition of the object under reduced pressure so that a metalcontained in this residue is vaporized, and a condensing means forcondensing the metal vaporized from the residue.

According to another aspect, a treatment method includes a first thermaldecomposition step of thermally decomposing an object containing resins,a first metal, and a second metal at a first temperature, a reformingstep of reforming a gaseous emission produced from the object at asecond temperature such that dioxins are decomposed, a cooling means forcooling the gaseous emission to a third temperature so that a rise inthe concentration of dioxins in the gaseous emission reformed at thesecond temperature is suppressed, a first reduced pressure heating stepof heating a residue produced by the thermal decomposition of the objectunder reduced pressure so that the first metal contained in this residueis vaporized and the second metal is maintained, a condensing step ofcondensing the first metal vaporized from the residue, and a secondreduced pressure heating step of heating the residue under reducedpressure so that the second metal contained in the residue from whichthe first metal is vaporized melts.

In the treatment method, in that in the second reduced pressure heatingstep, the residue is heated under reduced pressure so that the secondmetal contained in the residue from which the first metal is vaporizedmelts and coheres by its surface tension.

According to another aspect, a treatment method includes a thermaldecomposition step of thermally decomposing an object having resins andmetals as a part of its components and having a first portion and asecond portion which are bonded by a bonding metal while maintaining thebonding metal, a reforming step of reforming a gaseous emission producedfrom the object at a second temperature such that dioxins aredecomposed, a cooling step of cooling the gaseous emission to a thirdtemperature so that a rise in the concentration of dioxins in thereformed gaseous emission is suppressed, and a reduced pressure heatingstep of heating a residue produced by the thermal decomposition of theobject under reduced pressure so that the bonding metal is vaporized.

Moreover, the treatment method may further include a neutralizing stepof neutralizing the gaseous emission cooled by the cooling means.

It is recommended that the aforesaid thermal decomposition step beperformed in a non-oxidation atmosphere or a reducing atmosphere bycontrolling oxygen concentration or the like. Moreover, in the coolingstep, it is desirable to perform cooling to the third temperature in theshortest possible time, and more preferably within about ten seconds. Itis suitable to set the first temperature at about 250° C. to about 500°C. It is suitable to set the second temperature at a temperature higherthan about 800° C., and more preferably at a temperature higher than1000° C., and still more preferably at a temperature higher than 1200°C. It is suitable to set the third temperature at a temperature lowerthan 150° C., and more preferably at a temperature lower than 100° C.,and still more preferably at a temperature lower than 35° C.

The concentration of dioxins in the gaseous emission can be lowereddrastically by reforming and thermally decomposing the gaseous emissionemitted from the object to be treated at such a temperature that dioxinsare decomposed, shortening the retention time of the gaseous emission inthe temperature range in which dioxins are produced and recomposed fromthis state as much as possible, and cooling the gaseous emission to thethird temperature at which dioxins are not produced nor recomposed. Theconcentration of a production source of dioxins is sharply lowered bytreating the first thermal decomposition, the second thermaldecomposition, or the reforming at two stages of the first temperatureand the second temperature and simultaneously performing them in areducing atmosphere.

In this case, the second temperature is such a temperature that dioxinsare decomposed, and that not only dioxins but also other chemicalcompounds contained in the gaseous emission are also decomposed.Accordingly, not only dioxins but also halogenated hydrocarbon, PCB,coplanar PCB, and the like can be also decomposed and made innoxious.

Namely, to treat an object having resins and metals as its components, ameans for decomposing resins, a means for thermally decomposing furthera gaseous emission produced from the object to be treated, a coolingmeans for cooling the gases so that dioxins are not produced, and arecovery means for recovering a metal from a thermally decomposedresidue by vaporizing or liquefying it under reduced pressure areprovided, in which case the resins may be synthetic resins, naturalresins, or a mixture of these resins. Moreover, if not speciallyexplained, the metal here is the general term for metals contained inthe object to be treated, and not limited to a specific metallicelement.

The first thermal decomposition means is to thermally decompose theobject to be treated at the first temperature such that the object to betreated is thermally decomposed under controlled oxygen concentration,and extracts a gaseous emission, for example, from shredder dust, wastecircuit boards, and the like. Here, the gaseous emission is basicallycomposed of emitted gases, but the case where the gaseous emissioncontains solid fine particles, liquid fine particles mixed in theemitted gases is not excluded.

It is recommended that a heating means and a temperature measuring meansbe used as a temperature regulating means for regulating the firsttemperature in the first thermal decomposition means. As for a heatingmeans, it is suitable to select the heating means from various kinds ofheating such as convection heating, radiation heating, and the like asrequired or use them in combination as the heating means. For example,resistance heating by a sheathed heater or the like may be used, or gas,heavy oil, light oil, or the like may be combusted outside the chamber.Moreover, gases emitted from the resins of the object to be treated areturned into fuel gas after being reformed, made innoxious, orneutralized, and may be reused as a heat source of the treatmentapparatus, including the first thermal decomposition means. Furthermore,it is suitable to feed clean fuel gas, for example, obtained asdescribed above into a gas turbine generator, convert it to electricpower, and to use this electric power for the operation of the treatmentapparatus, including the first thermal decomposition means.

The use of various kinds of temperature sensors as the temperaturemeasuring means is recommended. It is recommended that the firsttemperature be set so that the resins of the object to be treated arethermally decomposed and that the metals of the object to be treated areoxidized as little as possible, but it is preferable to maintain thefirst thermal decomposition means on a reducing condition to eradicateproduction sources of dioxins at many stages as will be described later.For example, by thermally decomposing aromatic series hydrocarboncompounds containing chlorine under a reducing condition, chlorinecontained in the aromatic series hydrocarbon compounds is decomposedinto HCl and the like. Accordingly the production of dioxins issuppressed.

Incidentally, unless explained specially, polychlorinateddibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), andhomologues different from these in number of chlorine and substitutionposition are generically called dioxins. In addition, compounds in whichanother halogen is substituted for chlorine are included.

Therefore, it is suitable that the first thermal decomposition meansincludes a temperature regulating means and an oxygen concentrationregulating means since it is preferable that the metals contained in theobject to be treated are maintained so as not to be substantiallyoxidized, and more preferably in a reducing atmosphere.

Generally, when the object to be treated is complicated, there is apossibility that the object to be treated is partially oxidized, but itis only required to maintain a reducing atmosphere inside the firstthermal decomposition means as a whole. As the oxygen concentrationregulating means, for example, an oxygen concentration sensor which isan oxygen concentration measuring means and a carrier gas introductionsystem may be used.

As the oxygen concentration sensor, for example, a so-called zirconiasensor using zirconia (zirconium oxide) may be used, or the absorptionof CO and CO₂, for example, may be measured by infrared spectroscopy.Besides, GC-MS may be used. It is suitable that the oxygen concentrationsensor is selected from them as required or they are used in combinationas the oxygen concentration sensor.

A rare gas such as Ar or the like may be used as a carrier gas. Thiscarrier gas can not only regulate the oxygen concentration in the firstthermal decomposition means but also efficiently lead gases to thereforming means or the second thermal decomposition means. Moreover, theoxygen concentration regulating means may serve also as a pressureregulating means.

Moreover, a shredder may be provided at a stage prior to the firstthermal decomposition means. The object to be treated brought in fromthe outside of the apparatus may be introduced into the first thermaldecomposition means after being shredded by the shredder and segregated,or may be introduced into the first thermal decomposition means withoutbeing shredded. When the object to be treated is a waste circuit board,it is suitable to introduce it into the first thermal decompositionmeans without shredding it.

It is recommended that temperature and oxygen concentration conditionsin the first thermal decomposition means into which the object to betreated has been introduced be regulated so that the metals in theobject to be treated are oxidized as little as possible and so thatchlorine which has combined with organic compounds on the occasion ofthermal decomposition of the resins is made inorganic as much aspossible. The temperature and oxygen concentration conditions may be setpreviously, or may be controlled by feeding back measured values oftemperature and oxygen concentration to the heating means, the oxygenconcentration regulating means, and the like. When the oxygenconcentration needs to be measured, the used of a zirconia sensor or thelike is recommended.

The pressure in a chamber of the first thermal decomposition means maybe controlled. If the pressure in the first thermal decomposition meansis reduced, for example, the oxygen concentration is also lowered,whereby the object to be treated is not abruptly oxidized by heating. Alarge quantity of gases produced by decomposition are generated from theresins by heating, but generally resins hardly produce oxygen even ifthey are decomposed. Moreover, decomposition products of the resins areeasily vaporized.

Meanwhile, if the pressure is reduced, the thermal conductivity in thehermetic zone is lowered. But, if a non-oxidizing atmosphere ismaintained in the first thermal decomposition means, the object to betreated is not oxidized even under atmospheric pressure or underincreased pressure. Therefore, if the non-oxidizing atmosphere ismaintained in the first thermal decomposition means, pressurization ispossible, resulting in a rise in the thermal conductivity in the system.

A gaseous emission treatment system for treating a gaseous emission fromthe object to be treated will be explained now.

The gaseous emission treatment system is to treat the gaseous emissionemitted from the object to be treated by the first thermal decompositionmeans, and the principal portion thereof is composed of the reformingmeans or the second thermal decomposition means and the cooling means.The gaseous emission treated by the cooling means is utilized as cleanfuel gas by being subjected to post-treatment such as neutralization,filtration, or cleaning as required.

The reforming means is placed to connect with the first heating meansand reforms the gaseous emission emitted from the object to be treatedin the first thermal decomposition means at the second temperaturehigher than the first temperature, where reforming means thathydrocarbon compounds contained in the gaseous emission emitted from theobject to be treated are changed into lower-molecular hydrogen, methane,carbon monoxide, and the like. Moreover, hydroreforming or the like maybe performed. It is suitable in terms of the eradication of productionsources of dioxins as described above to perform reforming whilemaintaining the inside of the system on a reducing condition. If areducing atmosphere is maintained in the reforming means, a smallquantity of air may be introduced into the reforming means. As thereforming means, not only the thermal reforming means but also acatalytic reforming means by the use of a catalyst, for example, may beprovided in addition to this. As a catalyst, a metal such as Pt, Re, Ni,or V may be used being supported by various kinds of ceramics, solidacids such as alumina silica and zeolite (aluminosilicate).

Moreover, in place of the reforming means, the second thermaldecomposition means, connected to the first thermal decomposition means,for thermally decomposing the gaseous emission in a reducing atmospheremay be provided.

The gaseous emission from the object to be treated can be treated at thesecond temperature higher than the first temperature by separating thereforming means or the second thermal decomposition means from the firstthermal decomposition means, whereby the gaseous emission can bereformed effectively and chlorine is made inorganic effectively.

It is desirable to maintain the reforming means or the second thermaldecomposition means on such a condition that dioxins which directly orindirectly originate in the object to be treated are decomposed as muchas possible. Considerable dioxins can be decomposed, for example, bysetting the second temperature at about 800° C. Moreover, dioxins can bedecomposed more effectively by setting the second temperature at 1000°C. or higher, and more preferably at 1200° C. or higher. This reformingmeans performs treatment at the second temperature such that dioxins aredecomposed, and thus thermal decomposition of the gaseous emissionoccurs simultaneously at the second temperature.

Hydrocarbon compounds contained in the gaseous emission emitted from theobject to be treated are made lower-molecular and changed into hydrogen,methane, carbon monoxide, and the like by being reformed by thereforming means or by thermally decomposed by the second thermaldecomposition means. Further, when dioxins are contained in the gaseousemission, most of the dioxins are decomposed. Moreover, organic chlorineis made inorganic, and the recomposition of dioxins is suppressed.

Concerning the reforming means or the second thermal decompositionmeans, such a temperature condition that a reducing atmosphere anddioxins are decomposed by introducing the gaseous emission from thefirst thermal decomposition means and a small quantity of air into achamber filled with cokes may be formed.

Further, as described above, it is also suitable to heat the chamber tosuch a temperature that dioxins are decomposed by combusting fuel gasand air, and introduce the gaseous emission from the first thermaldecomposition means into this chamber as described above.

Furthermore, a catalytic cracking means such as a catalyst as describedabove may be provided in the chamber.

Additionally, a temperature regulating means and an oxygen concentrationmeasuring means for regulating the temperature and oxygen concentrationin the system may be provided in the reforming means or the secondthermal decomposition means as required. As the oxygen concentrationregulating means, such oxygen concentration sensor and carrier gasintroduction system as described above may be used. Moreover, a hydrogengas reservoir may be connected, or a reservoir for an inert gas such asAr may be connected.

As described above, the gaseous emission contained in the gaseousemission from the object to be treated is made lower-molecular by thereforming means or the second thermal decomposition means and changedinto hydrogen, methane, carbon monoxide, and the like. As for the firstthermal decomposition means, the reforming means or the second thermaldecomposition means, and the cooling means, the corrosion of containers,tubes, and the like caused by chlorine gas is severe in the case wherechlorine and the like are contained in the gaseous emission, and thushastelloy, titanium alloy, or the like in place of stainless steel maybe used for the apparatus as required.

The treatment apparatus includes the cooling means, placed to connectwith the reforming means or the second thermal decomposition means, forcooling the gaseous emission reformed or thermally decomposed at thesecond temperature to the third temperature so that a rise in theconcentration of dioxins in the gaseous emission is suppressed.

Namely, the concentration of dioxins in the gaseous emission reformed orthermally decomposed at the second temperature in the reforming means orthe second thermal decomposition means is extremely low, since thesecond temperature is a temperature such that the dioxins are decomposedand halogen in hydrocarbon compounds decomposed or reformed at thistemperature is made inorganic by a reducing atmosphere. Accordingly, inorder to prevent the production and recomposition of dioxins from thisstate, the gaseous emission is cooled to the third temperature so that arise in the concentration of dioxins in the gaseous emission issuppressed as much as possible. The third temperature may be set at sucha temperature that no production reaction of dioxins occurs.

The production and recomposition of dioxins can be suppressed, forexample, by cooling the gaseous emission in which dioxins are alreadydecomposed to 150° C. or lower, more preferably 100° C. or lower, andstill more preferably 50° C. or lower (since the temperature is requiredto be a temperature such that dioxins are decomposed even if it is notthe same as the temperature in the in the reforming means or the secondthermal decomposition means). On this occasion, it is desirable to coolthe gaseous emission to the third temperature in the possible shortesttime. This is because dioxins are easily produced and recomposed in therange of about 200° C. to about 400° C., and thus the concentration ofdioxins in the gaseous emission can be held down more effectively bycooling the gaseous emission to the third temperature to shorten theretention time of the gaseous emission in the temperature range in whichdioxins are easily produced and recomposed as much as possible.

Therefore, it is desirable to perform cooling of the gaseous emission inthe cooling means rapidly, preferably within about ten seconds.

As an example of such a cooling means, it is suitable to perform contactcooling by directly jetting a refrigerant such as water or cooling oilto the gaseous emission. On this occasion, if alkaline powder such aslime powder or the like is jetted to the gaseous emission, the gaseousemission is neutralized. Moreover, HCl in the gaseous emission, forexample, is spread over the surfaces of solids by touching the limepowder, which can also suppress the production and reproduction ofdioxins.

As described above, by means of the first thermal decomposition means,the reforming means or the second thermal decomposition means, and thecooling means, the gaseous emission from the object to be treated ischanged into hydrogen, methane, carbon monoxide, and the like, and theconcentration of dioxins in the gaseous emission is sharply lowered.

Herein, the production of dioxins is suppressed by treating thedecomposition of the object to be treated and the decomposition of thegaseous emission from the object to be treated at multiple stages by thefirst thermal decomposition means and the reforming means or the secondthermal decomposition means, and by maintaining such decomposition meanson a reducing condition.

When halides, SOx, NOx, and the like are contained in the gaseousemission cooled by the cooling means, the gaseous emission may becleaned and desulfurized by a cleaning means and a desulfurizing means,and the like. In addition, a filter means using activated carbon may beprovided.

Furthermore, the gaseous emission cooled in the cooling means may beintroduced to a neutralization reaction filter means such as a bagfilter. Between the cooling means and the neutralization reaction filtermeans, slacked lime, filter aid (for example, particles with high voidssuch as zeolite or activated carbon) and the like may be blown into acurrent of the gaseous emission by a dry venturi or the like.

The gaseous emission emitted from the object to be treated which hasbeen treated as above may be used as a heat source of heating by thefirst thermal decomposition means or may be supplied to a gas turbinegenerator to obtain electric power. Moreover, this electric power may beused for a heat source of the treatment apparatus and the like.

Next, the treatment of the thermally decomposed residue of the object tobe treated which is thermally decomposed by the first thermaldecomposition means will be explained.

In order to treat an object having resins and metals as a part of itscomponents, the treatment apparatus includes a means for decomposing andrecovering the resins and a means for separating and recovering themetals, and the reduced pressure heating means is a means for separatingand recovering the metals from the residue of the object to be treatedwhich is thermally decomposed by the first thermal decomposition means.It is recommended that such treatment be performed by the treatmentapparatus including the tube and the hermetic door.

Most of the resin components of the object to be treated are decomposed,and the gaseous emission is treated as described above by the firstthermal decomposition means. The oxygen concentration in the firstthermal decomposition means is controlled, and thus the metals in theobject to be treated are maintained in the object to be treated withoutbeing substantially oxidized and with only tiny vaporization takingplace. Meanwhile, most of the resins in the object to be treated remainas carbides as a result of thermal decomposition. Herein, the object tobe treated which is treated by the first thermal decomposition means istransferred from the first thermal decomposition means to the reducedpressure heating means.

The reduced pressure heating means provided in the treatment apparatusincludes a first hermetic zone partitioned from the first thermaldecomposition means by an openable and closeable partition and includinga temperature regulating means and a pressure regulating means forselectively vaporizing a metal in the object, and a first recoverymeans, connected to the first hermetic zone, for recovering the metalvaporized from the object. As such a recovery means, it is recommendedthat structure in which a hermetic door and a tube are combined asdescribed above be adopted.

Hereinafter, embodiments will be more specifically described withreference to the attached drawings.

EXAMPLE 1

FIG. 1 is a perspective view roughly showing an example of a treatmentapparatus, and showing the interior thereof by sectioning a portionthereof.

This treatment apparatus 100 can treat an object to be treated 150having resins and metals as its components, and it is composed of apurge chamber 101, a first hermetic chamber 102, a second hermeticchamber 103, and a cooling chamber 104.

These chambers are partitioned off by doors 105 which are openable andcloseable partitions. Namely, the outside of the apparatus and the purgechamber 101 are partitioned off by a door 105 a, the purge chamber 101and the first hermetic chamber 102 are partitioned off by a door 105 b,the first hermetic chamber 102 and the second hermetic chamber 103 arepartitioned off by a door 105 c, the second hermetic chamber 103 and thecooling chamber 104 are partitioned off by a door 105 d, and the coolingchamber 104 and the outside of the apparatus are partitioned off by adoor 105 e.

The doors 105 partitioning off these chambers include hermetic sealingmaintainability and heat insulating properties, and partition off therespective chambers in terms of heat and pressure. A thermal loadimposed on the door 105 a or 105 b is small, so that only themaintenance of hermetic sealing capability is required.

An exhaust system 106 is connected to the purge chamber 101. The exhaustsystem 106 includes an oil diffusion pump 106 a, a booster pump 106 b,and a rotary pump 106 c. Valves not illustrate are placed between thepurge chamber 101 and the exhaust system 106, and between respectivevacuum pumps. This point also applies to cases where it is not speciallydescribed below.

A trap 107 for trapping moisture, hydrogen gas, and the like emittedfrom the object to be treated 150 by pressure reduction in the purgechamber 101 and the like is placed between the purge chamber 101 and theexhaust system 106. Therefore, the emission of moisture, hydrogen gas,and the like from the object to be treated 150 in the purge chamber doesnot exert a harmful influence on the exhaust system 106. It isrecommended that this trap 107 be provided as required. Moreover, it isrecommended that an exhaust gas treatment system capable of decomposingor trapping dioxins which will be described later be provided in placeof the trap when the object to be treated such as soil or burned flyashes containing organic halides such as dioxins is treated. A wetfilter such as an oil film filter, a liquid seal pump, or the like maybe used as the trap.

The pressure in the purge chamber 101 is regulated by this exhaustsystem 106 and a vacuum gauge not illustrated which is a pressuresensor. It is suitable to use a Bourdon tube, a Pirani gauge, or thelike as the vacuum gauge as required.

A carrier gas introduction system for purging the interior of the purgechamber 101 by gas is connected to the purge chamber 101, and thenumeral 108 denotes a carrier gas introduction valve. The carrier gasintroduction system is connected to a carrier gas reservoir notillustrated. N₂ is used here as a carrier gas, but a rare gas such as Aror the like may be used.

It is also suitable to provide a heating means in the purge chamber 101to preheat the object to be treated 150.

The pressures in the purge chamber 101 and the first hermetic chamber102 are almost equalized, the door 105 b is then opened, and the objectto be treated 150 is moved to the first hermetic chamber 102 by a pusher130. Even when not specially described hereafter, it is recommended thatthe doors 105 be opened and closed after the pressures on both sides arebalanced. When a plurality of hermetic chambers are placed, the chambersmay be placed in an L-shape for the transfer of the object to betreated.

The first hermetic chamber 102 is a treatment chamber for thermallydecomposing component resins selectively while maintaining the oxidationstate of component metals of the object to be treated 150.

The first hermetic chamber 102 includes an electric heater 109 which isa heating means. Although a radiant tube is used here as the heatingmeans, the heating means is not limited to the aforesaid electric heater109, but may be selected or provided in combination as required. Forexample, gas, oil, or the like may be combusted or dielectric heatingmay be performed. Further, gases and oil which are thermal decompositionproducts of the component resins of the object to be treated 150 may becombusted.

The temperature in the first hermetic chamber 102 is regulated by thiselectric heater 109, a temperature sensor not illustrated, and a controlmeans not illustrated for controlling the electric heater by a measuredvalue from the temperature sensor. As for the control means, a programin which the measured value from the temperature sensor or a measuredvoltage is an input and a signal or a voltage such as changes electricpower to be supplied to the electric heater is an output, for example,is incorporated in an electronic computer and used as the control means.

Such a control may be performed by an analog circuit, or an operator mayoperate the heating means according to measured temperatures.

In the treatment apparatus illustrated in FIG. 1, the temperature in thefirst hermetic chamber 102 is controlled by the control means notillustrated collectively with the pressure and the oxygen concentrationin the first hermetic chamber 102, conditions in the purge chamber 101,the second hermetic chamber 103, and the cooling chamber 104, theopening and closing of the partitions 105, and the transfer of theobject to be treated 150, which will be described later. The controlmeans, for example, may include a control program in the electroniccomputer.

An exhaust system 110 is connected to the first hermetic chamber 102.The structure of this exhaust system is similar to that of the exhaustsystem 110 of the purge chamber 101.

The pressure in the first hermetic chamber 102 is regulated by thisexhaust system 110 and a vacuum gauge not illustrated which is apressure sensor. As described above, it is also suitable to use aBourdon tube, a Pirani gauge, or the like as the vacuum gauge asrequired. A carrier gas introduction system for regulating the oxygenconcentration in this chamber is connected to the first hermetic chamber102, and the numeral 112 denotes a carrier gas introduction valve. Thecarrier gas introduction system is connected to a carrier gas reservoirnot illustrated.

N₂ is used here as a carrier gas, but a rare gas such as Ar or air maybe used.

The pressure inside the first hermetic chamber can be reduced or raisedby properly operating the exhaust system 110 and the carrier gasintroduction valve 112. A pressure regulating means of this apparatuscan regulate the pressure in the system in the range of about 10⁻³ Torrto about 4×10³ Torr. The pressure may be reduced by changing thecapability and capacity of the exhaust system. Moreover, pressurizationmay be performed further by previously pressurizing the carrier gas.

The oxygen concentration in the first hermetic chamber 102 is regulatedby the carrier gas introduction valve 112 and an oxygen concentrationsensor not illustrated. A zirconia sensor, for example, may be used asthe oxygen concentration sensor. When the temperature in the firsthermetic chamber 102 is too low for the zirconia sensor, gas extractedfrom within the first hermetic chamber 102 may be regulated at about773K and the oxygen concentration may be measured.

In addition to the zirconia sensor, for example, the oxygenconcentration may be measured by infrared-spectroscopically analyzinggas in the system.

The oxygen concentration in the first hermetic chamber 102 may beregulated, for example, not by the introduction of the carrier gas suchas N₂ but by the total pressure in the system.

When thermal decomposition of component resins of the object to betreated 150 starts, a gas atmosphere produced by decomposition of theresins is distinguished in the first hermetic chamber 102. Therefore, ifthe oxygen concentration is fully lowered by reducing the pressure inthe first hermetic chamber 102 before the start of thermal decompositionof resins, the combustion of the object to be treated 150 and theoxidation of component metals of the object to be treated can beprevented.

It is recommended that the pressure and oxygen concentration in thefirst hermetic chamber 102 be controlled in the same manner as thetemperature as described above. A program in which measured values fromthe pressure sensor and the oxygen concentration sensor or a measuredvoltage is an input and a signal or a voltage for controlling a valve inthe exhaust system 110 and the carrier gas introduction valve 112 is anoutput, for example, may be incorporated in the electronic computer andused as a control means.

An exhaust gas treatment system 111 for treating a gaseous emissioncontaining gas produced by decomposition of the component resins of theobject to be treated 150 is placed between the first hermetic chamber102 and the exhaust system 110. The first hermetic chamber 102 and theexhaust gas treatment system 111 are partitioned off by an openable andcloseable hermetic door 111 b. When this hermetic door 111 b is opened,a retort 111 c is inserted from the exhaust gas treatment system 111side. On this occasion, the hermetic door 111 b is shielded from thefirst hermetic chamber 102, and the first hermetic chamber 102 and theexhaust treatment system 111 hermetically communicate with each other bythe retort 111 c. The adoption of this structure makes it possible toprevent the gaseous emission from adhering to the hermetic door 111 b inthe treatment apparatus. Moreover, a seal portion of the hermetic door111 b is shielded from heat from the first hermetic chamber 102, wherebythe seal portion of the hermetic door is protected, leading toimprovement in hermetic sealing capability.

In the exhaust treatment system, exhaust gas is made innoxious andvalues are recovered by condensing exhaust gas, decomposing the exhaustgas by a catalyst or plasma glow discharge, or adsorbing the exhaust gasby an adsorbent. For example, it is suitable to condense gases producedby the selective thermal decomposition of the object to be treated 150by the exhaust gas treatment system and recover them as oil such aslight oil and heavy oil, and tar. The recovered oil may be used as aheating means as described above.

When gases such as halogen and organic halides are contained in thegases produced by the decomposition of the component resins of theobject to be treated 150, the gases may be decomposed, for example, bythe use of a catalyst, plasma, and the like.

A multi-exhaust gas chamber not illustrated may be provided at stagessubsequent to the exhaust systems 106, 110, 114, and 115 connecting tothe respective chambers in order not to leak noxious gases emitted fromthe object to be treated 150 to the outside of the apparatus.

The temperature, pressure, and oxygen concentration in the firsthermetic chamber 102 are controlled as described above. Accordingly, thecomponent metals of the object to be treated 150 are hardly oxidized norvaporized, whereby the component resins can be thermally decomposedselectively. The gaseous emission produced by the thermal decompositionof the component resins is treated by the exhaust gas treatment system111. It is unnecessary to completely carbonize the component resins ofthe object to be treated in the first hermetic chamber 102, and it issuitable to thermally decompose the component resins to the extent thatthey are not obstacles when a metal is separated and recovered in thesecond hermetic chamber 103 at the next stage.

At the time of the completion of treatment in the first hermetic chamber102, most of the component resins remaining in the object to be treated150 exist as carbides.

In the treatment apparatus 100, the object to be treated 150 heated inthe first hermetic chamber 102 is moved to the second hermetic chamber103 without being cooled, resulting in very high thermal efficiency.

The second hermetic chamber 103 is a treatment chamber for selectivelyvaporizing and recovering the component metals of the object to betreated 150 from the object to be treated 150.

This second hermetic chamber 103 includes the same electric heater 109as the first hermetic chamber as a heating means. The heating member isnot limited to the electric heater 109, and can be selected or providedin combination as required.

As described above, the temperature in the second hermetic chamber 103is controlled by the electric heater 113 and a temperature sensor notillustrated similarly to that in the first hermetic chamber 102. Namely,the temperature in the second hermetic chamber 103 is controlled by thecontrol means not illustrated collectively with the pressure and theoxygen concentration in the second hermetic chamber 103, and withconditions in the purge chamber 101, the first hermetic chamber 102, andthe cooling chamber 104, and the opening and closing of the partitions105.

An exhaust system 114 is connected to the second hermetic chamber 103.The structure of this exhaust system is similar to that of the exhaustsystem 114 of the purge chamber 101.

The pressure in the second hermetic chamber 103 is regulated by thisexhaust system 114 and a vacuum gauge not illustrated which is apressure sensor. As described above, it is also suitable to use aBourdon tube, a Pirani gauge, or the like as the vacuum gauge asrequired. A carrier gas introduction system for regulating the oxygenconcentration in this chamber is connected to the second hermeticchamber 103, and the numeral 112 denotes a carrier gas introductionvalve. The carrier gas introduction system is connected to the carriergas reservoir not illustrated. N₂ is used here as a carrier gas, but arare gas such as Ar may be used.

The pressure in the first hermetic chamber can be reduced or raised byproperly operating the exhaust system 114 and the carrier gasintroduction valve 112. In this apparatus, the pressure in the systemcan be regulated in the range of about 10⁻³ Torr to about 4×10³ Torr.The pressure may be reduced by changing the capability and capacity ofthe exhaust system. Moreover, pressurization may be performed further bypreviously pressurizing the carrier gas.

The vapor pressures (boiling points) of the component metals of theobject to be treated 150 drop with pressure reduction in the secondhermetic chamber 103, whereby the metals can be vaporized at lowertemperatures.

Therefore, it is recommended that the capabilities of the heating meansand an exhaust means provided in the second hermetic chamber 103 bechanged according to the kind of metal separated and recovered from theobject to be treated 150.

A dielectric heating means may be provided, for example, to heat theinterior of the second hermetic chamber 103 to a higher temperature.Moreover, a vacuum pump with higher capability and a larger exhaustquantity may be provided, for example, to reduce the pressure in thesecond hermetic chamber 103 to form a higher vacuum. Depending on thecapacity of the interior of the second hermetic chamber 103, a stillhigher vacuum may be formed by using a getter-ion pump, aturbo-molecular pump, or the like.

The oxygen concentration in the second hermetic chamber 103 issufficiently low even if not specially regulated since the pressure inthe system is fully reduced. Hence, positive regulation is unnecessary,but when an oxygen concentration regulating means is provided, the samemanner as in the first hermetic chamber 102 can be recommended.

Although the structure in which one second hermetic chamber 103 isprovided is illustrated in the treatment apparatus 100 shown in FIG. 1,a plurality of second hermetic chambers 103 may be provided. Theprovision of the plurality of second hermetic chambers 103 different intemperature and pressure conditions therein enables a plurality ofmetals with different vapor pressures to be vaporized and recovered fromthe object to be treated 150.

When it is unnecessary to separate and recover individual elements ofmetals from the object to be treated 150, a plurality of metals can bevaporized and recovered from the object to be treated 150. When a Pb—Snalloy is removed from the object to be treated, for example, it issuitable to heat the object to be treated at such a temperature that Pband Sn are vaporized at the pressure in the second hermetic chamber 103and recover Pb and Sn. It is naturally suitable to selectively vaporizePb and Sn and recover them as separate fractions.

A recovery chamber 115 for recovering a metal in the state of a gasvaporized from the object to be treated 150 is placed between the secondhermetic chamber 103 and the exhaust system 114. This recovery chambercondenses the metal vaporized in this chamber by cooling them to atemperature not more than a melting point and recovers it. The secondhermetic chamber 103 and the recovery chamber 115 are partitioned off byan openable and closeable hermetic door 115 b. When the hermetic door115 b is opened 115 b, a retort (or a tube) 115 c is inserted from therecovery chamber 115 side. On this occasion, the hermetic door 115 b isshielded from the second hermetic chamber 103 and the recovery chamber115, and the second hermetic chamber 103 and the recovery chamber 115hermetically communicate with each other by the retort 115 c. Theadoption of the aforesaid structure makes it possible to preventvaporized substances from the object to be treated from condensing andadhering to the hermetic door 115 b in the treatment apparatus.Moreover, a seal portion of the hermetic door 115 b is shielded fromheat from the second hermetic chamber 103, whereby the seal portion ofthe hermetic door 115 b is protected, leading to improvement in hermeticsealing capability.

The recovery chamber 115 can be separated from the second hermeticchamber 103 if the hermetic door 115 b is closed by retreating theretort 115 c to the recovery chamber 115 side. In this state, the retort115 c can be exchanged by opening the recovery chamber 115 from theoutside. Accordingly, in the treatment apparatus, condensates vaporizedonce from the object to be treated can be taken out while the conditionssuch as the temperature, pressure, and the like in the second hermeticchamber 103 are maintained. Thus, continuous operation of the treatmentapparatus becomes possible, thereby drastically raising the productivityof treatment. The structure of this recovery chamber will be describedin detail on another occasion.

The interior of the retort 115 c placed in the recovery chamber 115 mayhave counter-current structure or helical structure. Even when thevaporized metal is continuously condensed and recovered, or condensedand recovered by batch processing, recovery efficiency increases if theretention time of the vaporized metal in the recovery chamber 115 islengthened. A valve, an openable and closeable partition, and a filterfor trapping vaporized substances and condensates which have not beenrecovered by the retort 115 c may be provided between the recoverychamber 115 and the exhaust system 114.

N2 or a rare gas as a carrier gas may be introduced into the secondhermetic chamber 103. The vaporized metal is efficiently introduced intothe recovery chamber by the carrier gas.

The recovery chambers 115 may be provided in plural lines in the secondhermetic chamber 103. It is suitable to recover the same metal by meansof the plurality of recovery chambers 115. Alternatively, it is suitablethat a plurality of metals are selectively vaporized by regulating thetemperature and pressure in the second hermetic chamber 103 stepwise andrecovered by switching the plurality of lines of recovery chambers 115.

The temperature, pressure, and oxygen concentration in the secondhermetic chamber 103 are controlled as above. Therefore, the componentmetal of the object to be treated 150 can be vaporized according to thevapor pressure thereof, and recovered in a metallic state by therecovery chamber 115.

Incidentally, the component resins sometimes emit gases produced bydecomposition and the like depending on the extent of thermaldecomposition of the component resins of the object to be treated 150 inthe first hermetic chamber. It is recommended that such gases producedby decomposition be treated by connecting a stage subsequent to therecovery chamber 115 to the exhaust gas treatment system 111, themulti-exhaust gas chamber not illustrated, or the like.

As described above, a predetermined metal can be vaporized and recoveredfrom the object to be treated in the second hermetic chamber 103.

If the object to be treated 150 is taken out from the second hermeticchamber 103 to the outside of the apparatus 100 directly, there is apossibility that the object to be treated 150 is oxidized rapidly.Moreover, the pressure in the second hermetic chamber 103 needs to bereturned to an atmospheric pressure and thus it is inconvenient also interms of the maintenance of hermetic sealing capability in the secondhermetic chamber 103. Therefore, in the treatment apparatus 100illustrate in FIG. 1 includes the cooling chamber 104 at a stagesubsequent to the second hermetic chamber 103.

This cooling chamber includes the same pressure regulating means andoxygen concentration regulating means as the purge chamber 101, thefirst hermetic chamber 102, and the second hermetic chamber 103, thatis, includes the same exhaust system 116 and carrier gas introductionvalve 117 as described above.

The object to be treated 150 from which the predetermined metal isseparated in the second hermetic chamber 103 is transferred to thecooling chamber 104, and cooled in a pressure- and oxygenconcentration-regulated state. The carrier gas not only regulates theoxygen concentration but also functions as a cooling gas for the objectto be treated 150.

A trap 118 for trapping gases emitted from the object to be treated bypre-heating may be placed between the cooling chamber 104 and theexhaust system 116.

After being fully cooled in the cooling chamber 104, the object to betreated 150 is taken out of the apparatus.

Such a treatment apparatus functions efficiently even when the object tobe treated capable of producing organic halides such as dioxins or theobject to be treated containing organic halides (for example, soil,burned fly ashes) is treated. This is because the partial pressure oforganic halides or components capable of producing organic halides in anatmospheric gas coexisting with the object to be treated is suppressedto the lowest since the object to be treated is heat-treated underreduced pressure. The concentration of dioxins contained in a residuelet out finally can be lowered by cooling a heated residue of the objectto be treated in the aforesaid gas which is substantially organichalide-free and not capable of producing organic halides. Incidentally,it is recommended that the object to be treated 150 be brought into thetreatment apparatus 100, taken out therefrom, and moved between therespective chambers by the pusher 130 and a drawer 131.

The operation of the pusher 130 and the drawer 131 together with theopening and closing of the partitions 105 may be performed by theaforesaid control means not illustrated.

FIG. 2 is a diagram schematically showing the treatment apparatusillustrated in FIG. 1. Signals from a pressure sensor 202 a in the purgechamber 101, a temperature sensor 201 a, a pressure sensor 202 b, and anoxygen concentration sensor 203 in the first hermetic chamber 102, atemperature sensor 201 c and a pressure sensor 202 c in the secondhermetic chamber 103, and a pressure sensor 202 d in the cooling chamber104, all of which are not illustrated in FIG. 1, are transmitted to acontrol panel 200 composing a control means. The control means may bestructured by incorporating a program into an electronic computer. It issuitable that the control means controls the heating means, the pressureregulating means, and the oxygen concentration regulating meansaccording to the state of each of the chambers in the apparatus.Moreover, the opening and closing of the partitions 105 and the transferof the object to be treated 150 by the pusher 130 and the drawer 131 maybe performed by this control means. The numeral 210 denotes a monitorfor showing the state of the temperature, pressure, oxygenconcentration, and the like in each chamber, the opening and closingstate of the partitions 105, and the like to the operator. The numeral211 denotes a multi-exhaust gas treatment device.

EXAMPLE 2

FIG. 3 is a diagram roughly showing another example of the treatmentapparatus, and showing the interior thereof by sectioning a portionthereof. This treatment apparatus 300 also can treat an object to betreated 350 having resins and metals as its components.

This treatment apparatus 300 is composed of a purge chamber 301, ahermetic chamber 302, and a cooling chamber 303. The hermetic chamber302 has both the functions of the first hermetic chamber 102 and thesecond hermetic chamber 103 in the treatment apparatus 100 illustratedin FIG. 1. Specifically, component resins of the object to be treated350 are thermally decomposed selectively in the hermetic chamber 302,and then a metal is separated and recovered in the same hermetic chamber302. Specially when a predetermined metal is isolated by the selectivethermal decomposition of resins, it is unnecessary to vaporize componentmetals of the object to be treated 350.

The hermetic chamber 302 includes a temperature regulating means, apressure regulating means, and an oxygen concentration regulating means,but the oxygen concentration may be also regulated by the total pressurein the hermetic chamber 302 as described above.

It is recommended that the temperature in the hermetic chamber 302 beregulated by an electric heater 309 and a temperature sensor notillustrated.

It is recommended that the pressure in the hermetic chamber 302 beregulated by exhaust systems 310 and 314, a carrier gas introductionsystem, and a pressure sensor not illustrated. The numeral 312 denotes acarrier gas introduction valve.

An exhaust gas treatment system 311 for treating a gaseous emissioncontaining gases produced by decomposition of the component resins ofthe object to be treated 350 is placed between the hermetic chamber 302and the exhaust system 310.

A recovery chamber 315 for condensing gas from the component metalvaporized from the object to be treated 350 is placed between thehermetic chamber 302 and the exhaust system 314. The structure of therecovery chamber 315 is similar to that described above. When thecomponent metals of the object to be treated do not need to bevaporized, a plurality of exhaust gas treatment systems 311 may beprovided.

The purge chamber 301, the cooling chamber 303, partitions 305, thecarrier gas introduction system, a pusher 330, and a drawer 331 aresimilar to those in the treatment apparatus 100 illustrated in FIG. 1. Acontrol means also can be provided in the same manner.

As described above, the treatment apparatus is most basically composedof a portion for thermally decomposing the component resins of theobject to be treated selectively so that the component metals areoxidized as little as possible. The category of an object capable ofbeing treated is greatly widened by combining the structure in which thecomponent metal is vaporized and separated from the object to betreated, and recovered, with this portion.

As for the treatment of resin-coated aluminum foil, aluminum can berecovered in a metallic state by thermally decomposing resinous portionsselectively under a controlled atmosphere.

As for the treatment of a mounting substrate in which electronic partsare mounted on a board or the like, it is suitable to vaporize andrecover a solder alloy and thereby separate the board and the electronicparts.

EXAMPLE 3

FIG. 4 is a diagram schematically showing another example of thetreatment apparatus.

This treatment apparatus 400 includes a first hermetic chamber 401 and asecond hermetic chamber 402. The first hermetic chamber 401 includes atemperature regulating means not illustrated and is connected to anexhaust system 403 and an exhaust gas treatment system 404. The secondhermetic chamber includes a temperature regulating means not illustratedand is connected to an exhaust system 405 and a recovery chamber 406. Acarrier gas introduction system 407 is connected to the first hermeticchamber 401 and the second hermetic chamber 402, and thus the regulationof the oxygen concentration and pressurization in each of the hermeticchambers can be performed. The numeral 408 denotes a carrier gasreservoir. The first hermetic chamber 401 and the exhaust gas treatmentsystem 404 are partitioned off by a hermetic door 404 b. When thehermetic door 404 b is open, a retort 404 c is inserted into an openingof the first hermetic chamber 401, whereby the retort 404 c shields thehermetic door 404 b from the first hermetic chamber 401 and the exhaustgas treatment system 404 and substantially allows the first hermeticchamber 401 and the exhaust gas treatment system 404 to hermeticallycommunicate with each other. Similarly, the second hermetic chamber 402and the recovery chamber 406 are partitioned off by a hermetic door 406b. When the hermetic door 406 b is open, a retort 406 c is inserted intoan opening of the second hermetic chamber 402, whereby the retort 406 cshields the hermetic door 406 b from the second hermetic chamber 402 andthe recovery chamber 406 and allows the first hermetic chamber 401 andthe exhaust gas treatment system 404 to hermetically communicate witheach other.

In this example, component resins of the object to be treated havingresins and metals are thermally decomposed selectively in the firsthermetic chamber 401, and gases produced by the decomposition aresubjected to treatment for making the gases innoxious in the exhaust gastreatment system 404. On this occasion, it is recommended that theresins be thermally decomposed selectively while the state of componentmetals of the object to be treated is maintained by regulating thetemperature, pressure, and oxygen concentration in the first hermeticchamber 401. Also, it is possible to equalize the structure of theexhaust treatment system 404 with that of the recovery chamber 406 andto condense vaporized substances from the object to be treated.

A reforming unit 409 for reforming a gaseous emission is placed on theexhaust gas treatment system 404 side in the first hermetic chamber 401.In this example, the reforming unit 409 includes a heating means such asa radiant tube and heats the gaseous emission to about 700° C. to about1200° C. to perform cracking under reduced pressure. For example, gasesproduced by the thermal decomposition of organic substances such asresins composing the object to be treated are reformed when passingthrough the reforming unit 409. As a result, the treatment of gases atthe subsequent stage is facilitated. Moreover, the performance ofreforming under reduced pressure can suppress the reproduction oforganic halides such as dioxins from the gaseous emission. Incidentally,in the reforming unit 409, not only cracking of the gaseous emission byheating but also reforming by glow discharge or plasma discharge orreforming by a catalyst may be performed.

When the gaseous emission is reformed by such a reforming unit 409, itis desirable to first exhaust the contents of the system by the exhaustsystem to make the reforming unit 409 reach a reforming temperature (inthe case of reforming by heating), thereafter to regulate thetemperature in the first hermetic chamber 401, and then to heat theobject to be treated. Even when the reforming unit 409 performsreforming by glow discharge or plasma discharge or reforming by acatalyst, it is suitable to heat the object to be treated after thereforming unit reaches a state capable of performing reforming. By thisstructure, even the gaseous emission in the process of a rise in thetemperature of the object to be treated can be reformed certainly. Forexample, when soil and burned fly ashes contaminated by organic halidessuch as dioxins are treated, dioxins (a solid, a liquid, a gas) areextracted or composed in the process of temperature rise from normaltemperature to about 500° C. According to the treatment apparatus, sucha gaseous emission produced in the process of temperature rise also canbe reformed certainly.

In the second hermetic chamber 402, the temperature and pressure thereinare regulated, and a component metal of the object to be treated isvaporized and then condensed in the recovery chamber 406. It isrecommended that the temperature and pressure in the second hermeticchamber 402 be regulated by the same control means as that of the firsthermetic chamber 401. A purge chamber may be placed at a stage prior tothe first hermetic chamber 401 or a stage subsequent to the secondhermetic chamber 402 as described above. Furthermore, the same reformingunit as that of the first hermetic chamber may be provided in the secondhermetic chamber.

EXAMPLE 4

FIG. 5 is a diagram schematically showing another example of thetreatment apparatus.

This treatment apparatus 500 is an apparatus capable of treating anobject to be treated having resins and metals as its components, andincludes a purge chamber 501, a first hermetic chamber 502, a secondhermetic chamber 503, a third hermetic chamber 504, and a coolingchamber 505.

The purge chamber 501 is connected to a trap 506 and an exhaust system507. The first hermetic chamber 502 is connected to an exhaust gastreatment system 508 and an exhaust system 509 via a hermetic door 508b. The second hermetic chamber 503 is connected to a recovery chamber510 and an exhaust system 511 via a hermetic door 510 b. The thirdhermetic chamber 504 is connected to a recovery chamber 512 and anexhaust system 513 via a hermetic door 512 b. The cooling chamber 505 isconnected to a trap 514 and an exhaust system 515. The first hermeticchamber 502, the second hermetic chamber 503, and the third hermeticchamber 504 include temperature regulating means not illustratedrespectively. The numeral 516 denotes a carrier gas introduction system,and the numeral 517 denotes a carrier gas reservoir.

The first hermetic chamber 502 includes an oxygen concentration sensornot illustrated, and can regulate the oxygen concentration in the systemindependent of total pressure.

Namely, the treatment apparatus 500 includes a plurality of treatmentchambers each for vaporizing a component metal of the object to betreated. Even when the object to be treated has a plurality of componentmetals, the plurality of metals can be vaporized selectively in thesecond hermetic chamber 503 and the third hermetic chamber 504, andrecovered.

EXAMPLE 5

FIG. 6 is a diagram schematically showing another example of thetreatment apparatus.

This treatment apparatus 600 is an apparatus capable of treating anobject to be treated having resins and metals as its components. In thistreatment apparatus 600, a plurality of recovery systems are connectedto one hermetic container 601, and treatment is performed by switchingthe recovery systems according to the temperature, pressure, and oxygenconcentration in the hermetic container 601. Also in this example, thehermetic container 601 and exhaust gas treatment systems 602 arepartitioned off by hermetic doors 602 b in the same manner as above.Moreover, the hermetic container 601 and the recovery chambers 605 arepartitioned by hermetic doors 605 b.

EXAMPLE 6

FIG. 7 is a diagram schematically showing the structure of a controlsystem 610 for regulating the temperature, pressure, oxygenconcentration in the hermetic container 601. It is suitable to controlthe apparatus by incorporating all or a part of a control means 611 intoan electronic computer, for example, as a control program as describedabove.

A plurality of lines of exhaust gas treatment systems 602 for recoveringgases produced by the decomposition of the component resins of theobject to be treated are connected to the hermetic container 601, andeach of the exhaust gas treatment systems 602 is connected to an exhaustsystem 603. Since gases produced by the decomposition of a resin aregenerally emitted in large quantities, the aforesaid provision of theplurality of exhaust gas treatment systems facilitates the control ofthe state of the interior of the hermetic container and lightens theburden imposed on the exhaust systems.

At a stage subsequent to the exhaust systems 603, an exhaust gastreatment device 604 for making noxious substances and the likecontained in exhaust gas innoxious, odorless, and smokeless. Forexample, dioxins, SOx, NOx, and the like which have passed through theexhaust systems 603 are treated to have values not more than theemission standard values by this exhaust gas treatment device 604, andlet out. This exhaust gas treatment device 604 may include a wet filtersuch as an oil film filter or a bag filter, an activated carbon filter,or the like.

A plurality of lines of recovery chambers 605 for recovering componentmetals of the object to be treated vaporized in the hermetic container601 are connected to the hermetic container 601, and the respectiverecovery chambers are connected to exhaust systems 606.

The plurality of lines of recovery chambers 605 connected to thehermetic container 601 may recover the same metal, or may recover aplurality of metals with different vapor pressures (boiling points) byperforming switching according to temperature and pressure conditions inthe hermetic container 601.

A carrier gas introduction system is connected to the hermetic container601. The numeral 607 denotes a carrier gas reservoir. The oxygenconcentration in the hermetic container 601 can be regulated independentof total pressure by the introduction of a carrier gas such as N₂ or Ar.Furthermore, pressurization inside the hermetic container 601 may beperformed by the introduction of a previously pressurized carrier gas.The decomposition efficiency of the component resins increases bypressurizing the object to be treated in a non-oxidizing atmosphere.

Moreover, the oxygen concentration in the hermetic container 601 may beregulated by total pressure.

EXAMPLE 7

FIG. 8 and FIG. 9 are diagrams schematically showing an example of thestructure of the recovery chamber of the treatment apparatus illustratedin FIG. 1 and FIG. 2. FIG. 8 shows a state in which the retort 115 cretreats into the recovery chamber 115 and the hermetic door 115 b isclosed. FIG. 9 shows a state in which the retort 115 c moves forward andis inserted into an opening 103 b of the second hermetic chamber 103 andthe hermetic door 115 b is open. The explanation centers here upon therecovery chamber, and the illustration of portions other than thischamber is omitted.

The recovery chamber 115 is placed adjacent to the second hermeticchamber 103 but partitioned therefrom by the openable and closeablehermetic door 115 b. The recovery chamber 115 includes a temperatureregulating means not illustrated. A carrier gas introduction system anda cooling gas introduction system may be connected to the recoverychamber 115. The recovery chamber 115 is provided between the secondhermetic chamber 103 and the exhaust system 114. The hermetic door 115 bis placed between the second hermetic chamber 103 and the recoverychamber 115 so as to partition off the second hermetic chamber 103 andthe recovery chamber 115. The retort 115 c is housed in the recoverychamber 115. The retort 115 c is an exchangeable tubular cassette forrecovering vaporized substances from the object to be treated, and inthis example, it has a hollow cylindrical shape having a second opening115 f in a face fronting the second hermetic chamber 103 and a thirdopening 115 d in a side face on the exhaust system 114 side. Gas flowingfrom the second hermetic chamber 103 to the exhaust system 114 gets intothe retort 115 c from the second opening 115 f of the retort, and is ledto the exhaust system 114 side through the opening 115 d in the sideface of the retort. A metallic net or the like may be provided insidethe retort 115 c so that the vaporized substances from the object to betreated can be easily condensed. In any case, it is recommended that theshape of the retort 115 c be designed to fit the opening 103 b of thesecond recovery chamber 103 as required. It is also recommended that theinner structure of the recovery retort be designed as required. Therecovery chamber 115 c has water cooling jacket structure and canmaintain the interior of the chamber at a temperature lower than thetemperature enabling the condensation of the vaporized substances.

This retort 115 c can be taken out by opening the recovery chamber 115while being separated from the second hermetic chamber 103 and theexhaust system 114, and set again in the recovery chamber 115.

The recovery chamber 115 includes a mechanism for moving the retort 115c forward and backward. In this example, the retort 115 c is movedforward and backward in the recovery chamber 115 by the extension andcontraction movement of a cylinder 115 d. The recovery retort 115 c isinserted into the opening 103 b of the second hermetic chamber 103 at aforward movement position. A plurality of cylinders may be provided forforward movement operation and backward movement operation. In thisexample, the cylinder 23 is covered with a bellows-shaped cover in orderto prevent the adhesion of vaporized substances to the cylinder 23. Amechanism for guiding the forward and backward movement of the retort115 c is provided in the recovery chamber 115. As such a guidemechanism, a guide rail, a guide roller, or the like may be used asrequired. This guide mechanism helps thermal conduction between therecovery chamber 115 and the retort 115 c. Thus, the guide mechanism maybe composed of metal with good thermal conductivity.

The operation of the treatment apparatus having the aforesaid recoverysystem will be explained now. First, the hermetic door 115 b is opened,and then the retort 115 c is moved forward and inserted into the opening103 b of the second hermetic chamber 103 (See FIG. 9). The hermetic door115 b is partitioned off from the second hermetic chamber 103 and therecovery chamber 115 by the recovery retort 115 c. The adoption of theaforesaid structure makes it possible to prevent the adhesion ofvaporized substances from the object to be treated to the hermetic door115 b. Furthermore, the hermetic door 115 b is shielded from radiationheat of the second hermetic chamber 103. Thus, a seal portion of thehermetic door 115 b is protected, leading to improvement in the hermeticsealing capability of the system.

After the retort 115 c is inserted into the opening 103 b of the secondhermetic chamber 103, the temperature and pressure in the secondhermetic chamber 103 are regulated to exceed a boiling point of adesired metal in the object to be treated to thereby vaporize the metal.Vaporized substances from the object to be treated are cooled whilegoing toward the exhaust system 114 through the retort 115 c, andcondensed in the retort 115 c. A filter for trapping the vaporizedsubstances which have not been condensed in the retort 115 c may beplaced between the recovery chamber 115 and the exhaust system 114,which can prevent the vaporized substances from the object to be treatedfrom reaching a vacuum pump. On this occasion, the hermetic door 115 bis shielded from a hot gas stream containing the vaporized substancesfrom the object to be treated by the retort 115 c. As a result, thecondensation of the vaporized metal from the object to be treated at theseal portion of the hermetic door 115 b can be prevented. Also whenresin is used for the seal portion of the hermetic door 115 b, the sealportion can be protected.

When vaporization treatment of a desired component from the object to betreated is completed, the retort 115 c is moved backward into therecovery chamber 115, and the hermetic door 115 b is closed (See FIG.8).

The recovery chamber 115 is separated also from the exhaust system 114by closing a valve between the recovery chamber 115 and the exhaustsystem 114. In this state, a hermetic door (the illustration of which isomitted) provided in the recovery chamber 115 is opened, and the retort115 c is taken out. Condensates in the retort 115 c are in a metallicstate or in an unstable state with a large specific surface area, andhence it is desirable to cool the condensates by introducing gas such asnitrogen, carbon dioxide, or an inert gas before opening the recoverychamber 115. Thereafter, another retort is set in the recovery chamber115, and the same operation is repeated. The provision of such arecovery chamber 115 enables conditions such as temperature, pressure,oxygen concentration, and the like in the second hermetic chamber 103and the recovery chamber 115 to be controlled independent of each other.Consequently, the operational efficiency of the apparatus is raised.Such a recovery chamber can naturally be applied to the respectiverecovery chambers of the treatment apparatus shown in FIG. 3, FIG. 4,FIG. 5, and FIG. 6. The same structure can be adopted for a connectionportion of the exhaust gas treatment system and the hermetic chamber. Byadopting the aforesaid structure, in the treatment apparatus, thevaporized substances from the object to be treated and thermaldecomposition products such as a gaseous emission can be recovered whilea heating furnace is continuously operated without being stopped whenthe pressure in the heating furnace is decreased or increased. Thereby,the productivity of treatment is raised, resulting in a reduction intreatment costs.

EXAMPLE 8

FIG. 10, FIG. 11, and FIG. 12 are diagrams roughly showing an example ofthe structure of the treatment apparatus. FIG. 10 shows a state in whichthe retort is set in the recovery chamber, FIG. 11 shows a state inwhich the retort is inserted into the hermetic chamber, and FIG. 12shows a state in which the recovery chamber is opened for exchange ofretorts. Incidentally, explanation will be given here with the treatmentapparatus shown in FIG. 1 and FIG. 2 as the example thereof, but thestructure of this recovery system can be applied to other treatmentapparatus similarly.

As described above, the second hermetic chamber 103 is partitioned offfrom the recovery chamber 115 by the openable and closeable hermeticdoor 115 b. The recovery chamber 115 is connected to the exhaust system114 through an opening 17. The numeral 14 denotes a housing chamber inwhich the hermetic door 115 b is housed when being opened, and thenumeral 15 is a cylinder for opening and closing the hermetic door 115b. The retort 115 c is housed in the recovery chamber 115. The retort115 c is an exchangeable tubular cassette for recovering the vaporizedsubstances from the object to be treated, and in this example, it has ahollow cylindrical shape having the opening in a face fronting thesecond hermetic chamber 103 and the opening (115 d) in a side face onthe exhaust system 114 side. The recovery chamber 115 includes amechanism for moving the retort 115 c forward and backward. In thisexample, the retort 115 c moves forward and backward in the recoverychamber 115 by the extension and contraction motion of cylinders 23 and31. The recovery retort 115 c is inserted closely into the opening 103 bof the second hermetic chamber 103 at a forward movement position. Aplurality of cylinders may be provided for forward movement operationand backward movement operation. In this example, the cylinder 23 iscovered with a bellows-shaped cover 30 in order to prevent the adhesionof vaporized substances to the cylinder 23. A mechanism for guiding theforward and backward movement of the retort 115 c is provided in therecovery chamber 115. As such a guide mechanism, a guide rail, a guideroller, or the like may be used as required.

FIG. 11 shows a state in which the hermetic door 115 b is opened, andthen the retort 115 c is moved forward and inserted into the opening 103b of the second hermetic chamber 103. The hermetic door 115 b is blockedoff from the second hermetic chamber 103 and the recovery chamber 115 bythe recovery retort 115 c. The adoption of the aforesaid structure makesit possible to prevent the adhesion of the vaporized substances from theobject to be treated to the hermetic door 115 b. Furthermore, thehermetic door 115 b is shielded from radiation heat of the secondhermetic chamber 103. Thus, the seal portion of the hermetic door 115 bis protected, leading to improvement in the hermetic sealing capabilityof the system. In this state, the temperature and pressure in the secondhermetic chamber 103 are regulated to exceed a boiling point of adesired metal in the object to be treated to thereby vaporize the metal.Vaporized substances from the object to be treated are cooled whilegoing toward the exhaust system 114 through the retort 115 c andcondensed in the retort 115 c. On this occasion, the hermetic door 115 bis shielded from a hot gas stream containing the vaporized substancesfrom the object to be treated by the retort 115 c. As a result, thecondensation of the vaporized metal from the object to be treated at theseal portion of the hermetic door 115 b can be prevented. Also whenresin is used for the seal portion of the hermetic door 115 b, the sealportion can be protected.

When vaporization treatment of a desired component from the object to betreated is completed, the retort 115 c is moved backward into therecovery chamber 115, and the hermetic door 115 b is closed (See FIG.10).

The recovery chamber 115 is separated also from the exhaust system 114by closing the valve between the recovery chamber 115 and the exhaustsystem 114. In this state, a hermetic door 33 provided in the recoverychamber 115 is opened, and the retort 115 c is taken out (FIG. 12).Since the hermetic door 115 b is shielded from the second hermeticchamber 103 during the recovery of the vaporized substances from theobject to be treated, the adhesion of condensates to the hermetic door115 b is prevented. Moreover, damage caused to the seal portion of thehermetic door 115 b by heat is also prevented. Consequently, even if therecovery chamber 115 is opened, the leakage of outside air into thesecond hermetic chamber 103 can be prevented. Thereafter, another retortis set in the recovery chamber 115, and the same operation is repeated.By adopting the aforesaid structure, herein, the vaporized substancesfrom the object to be treated and thermal decomposition products such asa gaseous emission can be recovered while a heating furnace iscontinuously operated without being stopped even when the pressure inthe heating furnace is decreased or increased. Thereby, the productivityof treatment is raised, resulting in a reduction in treatment costs.

FIG. 12 is a diagram roughly showing an example of the structure of anexhaust gas treatment device for treating exhaust gas emitted from theobject to be treated but not recovered in the exhaust gas treatmentsystem, the recovery chamber, and the like. A multi-exhaust gastreatment filter 1201, a filter 1202 for making exhaust gas smokeless,and a filter 1203 for making exhaust gas odorless are connected at astage subsequent to the exhaust gas treatment system or the recoverysystem such as the recovery chamber. In addition to the above, forexample, an alkali trap for recovering halogen gas, a halogenatedhydrocarbon decomposition device using a catalyst, and the like may beprovided.

As described above, with respect to the object to be treated havingresins and metals as components, the treatment apparatus can separatethem from the object to be treated and recover them by thermallydecomposing (vaporizing, liquefying, or carbonizing) the componentresins selectively and by vaporizing the component metals.

EXAMPLE 9

Next, a treatment system for removing lead from an object having lead asits component will be explained.

This treatment system is intended for the treatment of an object inwhich lead and resins are used for at least a part of components. Forexample, it can remove lead from electronic equipment, automotiveelectronic parts, and the like in which an alloy containing lead such asa PB-Sn series solder alloy is used.

This treatment system first thermally decomposes resinous portionsselectively by vaporization, liquefaction, carbonization, or the like,and then separates lead from the object to be treated by vaporizing thelead. It is recommended that the vaporized lead be recovered. Thetreatment apparatus described above may be used as its apparatus.

First, the component resins are thermally decomposed selectively so thatlead contained in the object to be treated is not substantiallyoxidized.

The resins melt from about 323K, and emits mainly hydrocarbon gases ofC1 to C8 by thermal decomposition if being maintained at about 453K toabout 873K. It is recommended that the aforesaid gases produced by thedecomposition of resins be recovered by the exhaust gas treatment systemor the like.

It is desirable to perform this selective thermal decomposition processof resins in a state in which the oxygen concentration is regulated. Theregulation of oxygen concentration improves the recovery efficiency ofgases produced by the decomposition of resins, and can prevent theoxidation of lead. Since lead oxide vaporizes at a temperature lowerthan lead, lead can be prevented from flying about, and lead can berecovered more positively at the following process.

The temperature and pressure are regulated, and then lead is vaporizedfrom the object to be treated. When the object to be treated containsmetals such as iron, copper, aluminum, and tin other than lead, it isrecommended that the metals be vaporized selectively from a differencein vapor pressure.

The temperature at which lead vaporizes changes depending on thepressure in the hermetic container. When being is heated, for example,to 1673K under atmospheric pressure, the vapor pressure of lead is 84mmHg, whereas the vapor pressures of iron, copper, and tin do not reacheven 1 mmHg. Therefore, almost only lead vapor can be selectivelygenerated from the object by heating the object to about 1673K.

When being heated, for example, to 2013K under atmospheric pressure, thevapor pressure of lead is 760 mmHg, whereas the vapor pressure of tin is15 mmH, and the vapor pressure of copper does not reach even 3 mmHg.Therefore, almost only lead vapor can be selectively generated from theobject by heating the object to about 1673K.

Further, lead in the object to be treated can be vaporized at a lowertemperature by heating the object to be treated under reduced pressure.

If the pressure is regulated at 10⁻¹ Torr, almost only lead vapor can beselectively generated from the object to be treated by heating theobject to about 1100K.

If the pressure is regulated at 10⁻³ Torr, almost only lead vapor can beselectively generated from the object to be treated by heating theobject to about 900K.

Furthermore, if the pressure is regulated at 10⁻⁴ Torr, almost only leadvapor can be selectively generated from the object to be treated byheating the object to about 700K.

It is recommended that the lead vapor generated selectively as describedabove be recovered as metallic lead by the recovery device cooled to themelting point of lead or lower.

FIG. 13 is a graph showing the relationship between the vapor pressureof lead and the temperature thereof. It can be seen that the boilingpoint of lead lowers if the pressure in the hermetic container isreduced.

It is suitable to regulate heating temperature, for example, accordingto the pressure in the hermetic container based on this graph. It isalso suitable to incorporate this relationship as a program in anelectronic computer and use it as the aforesaid control means of thetreatment apparatus.

EXAMPLE 10

An example in which a mounting substrate in which various kinds ofelectronic parts are mounted on a circuit board with a solder alloycontaining Pb as an object to be treated is treated will now beexplained as an example of an object having lead and resins as itscomponents.

FIG. 14 is a diagram schematically showing such a mounting substrate1300.

Electronic parts 1304 is mounted on a circuit board 1303 in which copperfoil 1301 and resins 1302 are laminated. The electronic parts 1304 arepackaged by resins 1305. A connecting terminal 1306 of the electronicparts, made of a Cu alloy, and the copper foil are bonded with a Pb—Snseries solder alloy 1307. The surface of the connecting terminal 1306 ofthe electronic parts is sometimes plated with a solder alloy, in whichcase treatment can be performed in the same manner.

First, the mounting substrate 1300 is heated in the hermetic containerwhere the oxygen concentration is regulated, and the resins 1302 and1303 are thermally decomposed selectively. Component resins of aprint-circuit board are generally thermosetting resins and mostlycarbonized, but a large quantity of gases produced by decomposition areemitted. This applies to the packaging resins 1303 for the electronicparts.

FIG. 15 is a diagram schematically showing the mounting substrate 1300in which the component resins are thermally decomposed selectively.

In this state, most of the component resins of the mounting substrateare carbonized. Lead never flies about by regulating the oxygenconcentration.

Subsequently, lead contained in the object to be treated is selectivelyvaporized in the hermetic container where the temperature and pressureare regulated. It is recommended that the temperature and pressure bedecided based on FIG. 13. It is desirable to reduce the pressure in thehermetic container. This is because energy to be supplied becomessmaller since lead is vaporized at a lower temperature, and componentmetals of the object to be treated such as lead and the like are notsubstantially oxidized since the oxygen concentration becomes lower.When there is a possibility that the component metals of the object tobe treated are oxidized, it is recommended that a carrier gas such as N₂or Ar be introduced to regulate the oxygen concentration in the hermeticcontainer.

As the pressure in the hermetic container is reduced more, lead isvaporized at a lower temperature. FIG. 16 is a diagram schematicallyshowing a state in which lead 1308 is vaporized in a metallic state.Only lead can be vaporized selectively by regulating the temperature andpressure in the hermetic container. When metals with boiling pointslower than lead are contained in the object to be treated, it is betterto vaporize such metals earlier.

As described above, lead can be removed from the mounting substrate 1300which is the object to be treated. Further, a large amount of wasteelectronic equipment in society can be disposed of as non-industrialwastes by treating mounting substrates of the waste electronicequipment, and the contamination of the environment by the elution oflead is eliminated. The separation of component metals other than leadis facilitated, and those metals can be utilized as resources. Thecomponent resins can be recovered as valuable oil or carbides. Thecarbides may be utilized as fertilizer and activated carbon.

Although processes until lead is removed from the mounting substrate1300 are explained above, component metals other than lead of the objectto be treated may be vaporized by further regulating the temperature andpressure in the hermetic container.

For example, the circuit board 1303 and the electronic parts 1304 can beseparated by vaporizing tin composing the solder alloy.

FIG. 17 is a diagram schematically showing a state in which tin isvaporized and thereby the circuit board 1303 and the electronic parts1304 are separated.

The aforesaid removal of lead and separation of the circuit board 1303and the electronic parts 1304 reduce complexity owned by the object tobe treated, leading to facilitation of the following treatment. In otherwords, the entropy of the object to be treated reduces, which can raisethe value of the object.

Metals such as Au, Ag, Pt, Bi, In, Ta, Ni, Cr, Cu, Al, W, Mo, Co, and Pdcontained in the circuit board 1303 and the electronic parts 1304 may bevaporized and recovered by regulating the temperature and pressure inthe hermetic container. Such recovery becomes more efficient if therecovery is performed after the circuit board 1303 and the electronicparts 1304 are separated.

FIG. 18, FIG. 29, and FIG. 30 are diagrams showing pressure dependencyof the boiling points (vapor pressures) of various kinds of metals.These diagrams illustrate recoverable metals, but metals not illustratedalso can be recovered.

FIG. 19 is a diagram showing temperature dependency of production freeenergy of oxides. Elements illustrated in FIG. 19 are shown as oneexample, but data concerning elements other than these elements also canbe obtained easily by computation or a data base. It is recommended thatthe temperature, pressure, oxygen concentration in the hermeticcontainer, for example, be controlled by using the relations shown inFIG. 18, FIG. 19, FIG. 29, and FIG. 30 together with the relationbetween the boiling point (vapor pressure) of lead and pressure.

It is also suitable to incorporate these relations as a program in anelectronic computer and use it as the aforesaid control means of thetreatment apparatus.

EXAMPLE 11

FIG. 20 is a diagram schematically showing an example of an apparatusused for removing lead contained in the object to be treated having leadand resins as its components. The apparatus is not limited to theapparatus illustrated in FIG. 20, and the treatment apparatus describeduntil now can be used.

This treatment apparatus 2000 includes a first hermetic chamber 2001 anda second hermetic chamber 2002. The first hermetic chamber 2001 includesan oxygen concentration control device 2003 and a heating device notillustrated such as a burner, and it is maintained at a predeterminedtemperature for a predetermined period of time by a control section theillustration of which is omitted.

Hydrocarbon gas emitted from component resins by heating an object to betreated 2004 is cooled and recovered as oil in a liquefaction andrecovery device 2005. The numeral 2006 denotes an exhaust gas cleaningdevice, and in this example, an alkaline water shower cleaning device orthe like is connected, and halogen gas contained in exhaust gas isreduced to a value not more than the environmental standard.

The second hermetic chamber 2002 is a vacuum heating furnace, and has alead recovery chamber 2007 and an exhaust device 2008.

Objects to be treated are sent to the first hermetic chamber 2001 andthe second hermetic chamber in sequence by a moving means 2009 such as aconveyor.

The retention time, heating temperature, pressure, and oxygenconcentration in the first hermetic chamber 2001 and the second hermeticchamber 2002 of these objects to be treated are respectively controlledby a control section not illustrated.

The objects to be treated are sent to a residue catching section 2010after passing through the second hermetic chamber 2002.

In the first hermetic chamber 2001, the temperature of the object to betreated 2004 is increased to and maintained at about 473K to about 873K.The component resins which are a part of components of the object to betreated 2004 are thermally decomposed and emitted as hydrocarbon gases,for example, C1 to C8 and C8 to C16.

The gases produced by the decomposition of resins and emitted arecondensed and recovered by the exhaust gas treatment system 2005.Unrecovered gases are removed by the exhaust gas cleaning device 2006,and made innoxious, smokeless, and odorless.

Thereafter, the object to be treated 2004 is sent to the second hermeticchamber 2002, and the pressure is reduced, for example, to about 10⁻⁵Torr, the temperature is regulated at about 700K, and this condition ismaintained. Lead in the object to be treated is emitted as vaporizedlead from the object to be treated. A gas exhaust section is provided atthe upper portion of the second hermetic chamber 2002, and the vaporizedlead emitted form the object to be treated is condensed as metallic leadby a reduction in vapor pressure. Crystallized metallic lead isdeposited and recovered in the lead recovery chamber 2005. An inert gassuch as N₂ or Ar is introduced from a carrier gas introduction sectionprovided in the second hermetic chamber 2002 in order to efficientlyfeed vaporized lead from the second hermetic chamber 2002 to the leadrecovery chamber 2005, and the vaporized lead together with the carriergas is fed to the lead recovery chamber 2005.

A gas exhaust section is provided at the upper portion of the firsthermetic chamber, and the gases produced by the decomposition of resinsand emitted are sent to the exhaust gas treatment system 2005.

The exhaust gas treatment system 2005 mainly recovers heavy oil when thecooling temperature is 523K to 423K, a mixture of heavy oil and lightoil when it is 423K to 323K, and light oil when it is 323K to roomtemperature. The recovered oil is led to a recovery tank theillustration of which is omitted, and can be reused as fuel or a rawmaterial.

Gas exhausted from the exhaust gas treatment system 2005 is led to theexhaust gas cleaning device 2006 via a gas delivery section 15. In thisexample, the alkaline water shower cleaning device is connected, andhalogen gas contained in the exhaust gas is reduced to a value not morethan the environmental standard.

EXAMPLE 12

Next, an example in which electronic equipment containing solder istreated as an object to be treated by using the treatment apparatus 2000structured as above will be explained.

The electronic equipment which is the object to be treated 2004 may becrushed in pretreatment. Electronic parts are coarsely crushed here intoabout 10 centimeters square by a double spindle-type crusher. Thecoarsely crushed electronic equipment is thrown into the first hermeticchamber.

The first hermetic chamber 2001 is maintained at a furnace temperatureof about 773K and an oxygen concentration of about 5%, and theelectronic equipment is held therein for about 30 minutes. Componentresins accounting for about 40% of components of the electronicequipment are thermally decomposed selectively in the first hermeticchamber 2001, and emitted as hydrocarbon gas or carbonized.

Chemical change is not caused to metals such as iron, copper, andaluminum accounting for about 50% of components and a mounting substrateaccounting for about 10% of components in the first hermetic chamber2001. Namely, an oxidation state and a phase equilibrium state aresubstantially maintained.

The electronic equipment in which the components resin are thermallydecomposed selectively is transferred to the second hermetic chamber2002 without being cooled. The second hermetic chamber 2002 ismaintained at a pressure of about 10⁻³ Torr and a temperature of about900K, and the electronic equipment is held therein for about 30 minutes.

A solder alloy weighing about 5% to 10% of the substrate weight is usedin the mounting substrate accounting for about 10% of components of theelectronic equipment. About 40 wt % of this solder alloy is lead.

Namely, 0.2% to 0.4% lead is used as a part of components in theelectronic equipment. The lead is vaporized as vaporized lead in thesecond hermetic chamber 2002, fed together with a carrier gas to thelead recovery chamber 2005, and recovered as metallic lead.

To raise the recovery percentage of lead, it is desirable to lengthenthe retention time of lead vapor in the lead recovery chamber 2005 aslong as possible. In this example, the recovery percentage of lead is98%. The recovered lead has few impurities, and can be reused asvaluable metal.

The hydrocarbon gas thermally decomposed and emitted in the firsthermetic chamber 2001 is fed to the exhaust gas treatment system 2005and cooled in a condensing section cooled by circulating water at about300K. In this example, 40% of the electronic equipment is composed ofresins. The liquefaction percentage differs depending on components ofthe component resins, but about 90% of weight percentage is recovered asoil, and about 10% thereof remains as a residue mainly composed ofcarbides.

The recovered oil can be recycled as fuel or a raw material. Gascomponents which have passed through the exhaust gas treatment system2005 are released into the atmosphere as exhaust gas with a value notmore than the environmental standard by being cleaned in the exhaust gascleaning device 2006. Metals such as iron, copper, and aluminumaccounting for about 50% of components of the electronic equipment arehardly oxidized in the first hermetic chamber 2001 and the secondhermetic chamber 2002, and if anything, they are reduced and can berecovered as metals, resulting in high recycling value.

In this example, residues let out into the residue catching section 30are mainly iron, copper, aluminum, and a carbide residue of resins.

FIG. 21 is a diagram schematically showing an example of openable andcloseable partitions 2101 for maintaining hermetic sealing capabilitiesand heat insulating properties of the first hermetic chamber 2001 andthe second hermetic chamber 2002 in the treatment apparatus 2000illustrated in FIG. 20. The partitions 2101 are operated by wires 2102and winding machines 2103.

A vacuum door and a heat insulating door may be provided separately atthe position of each of the partitions 2101. For example, it is suitablethat a vacuum door is used as the partition 2101 b, and that on thefirst hermetic chamber 2001 side and on the second hermetic chamber 2002side of this door, openable and closeable heat insulating doors areplaced.

Next, wastes containing resins and metals which are used in largequantities in various kinds of electronic equipment, automobiles,precision equipment, stationary, packages for medical supplies andgroceries, and so on will be taken up as the object to be treated andthe treatment system thereof will be explained. As for an apparatus, itis recommended that the treatment apparatus described above be used.

EXAMPLE 13

Such wastes containing resins and metals are difficult to separate andrecover, and hence they are generally treated by combustion andreclamation. In the treatment system, in the same apparatus, thecomponent resins of the wastes are thermally decomposed (vaporized,liquefied, or carbonized) selectively, and the component metals arevaporized and recovered in a metallic state. Specially, wastescontaining resins are slow in temperature increase under reducedpressure, which is practically the problem, but herein, this problem issolved by regulating oxygen concentration.

In the treatment system, wastes containing resins and metals are firstthrown into the hermetic container. The oxygen concentration isregulated to recover resinous portions, and pressurization to severalatmospheres and heating are performed. Then, pressure reduction andheating is performed to vaporize and recover the metals.

FIG. 22 is a diagram schematically showing an example of the treatmentapparatus which can be used in this treatment system.

Wastes containing metals and resins are housed in a hermetic container2201, a throw shelf 2202 made of metal with high temperature increaseefficiency and high heat resistance is provided in the hermeticcontainer. The numeral 2203 is a door for opening and closing thehermetic container 2201. A heating device 2204 such as a sheathed heateror the like is provided in the hermetic container, and operated togetherwith the pressure and oxygen concentration in the hermetic container bya control panel 2205. The numeral 2206 denotes a sensor, and ittransmits the temperature, pressure, and oxygen concentration in thehermetic container 2201 as signals to the control panel 2205.

The hermetic container 2201 is connected to an exhaust device 2208. Aresin recovery system 2209 which is a recovery device for gases producedby decomposition of the component resins of the wastes and a metalrecovery system 2210 which is a recovery device for the component metalsof the wastes are placed between the hermetic container 2201 and theexhaust device 2208. The resin recovery system 2209 may include, forexample, an exhaust gas treatment system or the like. The metal recoverydevice may include, for example, a cyclone separator.

The wastes are thrown into the throw shelf 2202 provided in the hermeticcontainer 2201, the door 2203 is closed to hermetically seal thecontainer, and heating (400° C.) and pressurization (3 atm) are firststarted in a state in which the recovery system is closed.

In this case, temperature increase efficiency is higher than heatingunder reduced pressure, which contributes to temperature increaseefficiency in heating under reduced pressure at the time of thefollowing recovery of metals.

Gases produced by thermal decomposition of the component resins of thewastes are recovered by a plurality of recovery devices according to thetypes of gases. When the wastes contain polyvinyl chloride resins, it issuitable to first heat them under normal pressure to generate chlorinegas. It is recommended that this chlorine gas be recovered as ironchloride by being brought into contact with iron heated to a hightemperature, or be recovered as ammonium chloride by adding ammonia. Inthis case, the corrosion of the container, tubes, and the like bychlorine gas is severe, and thus hastelloy, titanium alloy, or the likein place of stainless steel may be used for the apparatus as required.Incidentally, exhaust gas such as unrecovered gas may be made innoxiousby high-temperature combustion.

A part of resins are carbonized and can be reused for fertilizer, fuel,and the like. Carbides subjected to vacuum heat treatment have excellentcapability for fertilizer, fuel, deodorant, and the like. Then, theresin recovery system 2209 is closed, and a circuit for another pipe forthe metal recovery system 2210 is opened. The pressure in the hermeticcontainer 2201 is reduced to about 10⁻³ Torr by the exhaust device, thehermetic container is heated to a temperature not less than a boilingpoint of the alloy according to the kind of metal to vaporize the metal,and the metal is recovered by a condensing means placed midway in themetal recovery system 2210. In this case, the vaporization temperatureof metal is lower than under normal pressure, which enables relativelylower heating temperature and uneasy oxidation, resulting in goodrecovery efficiency.

As described above, according to the treatment system, thermalefficiency is favorable and treatment costs are low. Furthermore, theperformance of heating and pressurization enables favorable recoveryefficiency of oil with relatively small molecular weight, and heatingunder vacuum enables high recovery percentage of metal with high purity.

EXAMPLE 14

Next, waste mounting substrates, in each of which various kinds ofelectronic parts are mounted on a circuit board, used in largequantities in various kinds of electronic equipment, automobiles,precision equipment, and so on will be taken up as the object to betreated, and the treatment system thereof will be explained. As for anapparatus, it is recommended that the treatment apparatus describedabove be used.

This treatment system efficiently separates and recovers electronicparts from a mounting substrate on which various kinds of electronicparts such as an IC, an LSI, a resistor, a capacitor, and the like aremounted, and also separates and recovers component resins and componentmetals of the mounting substrate composed of a circuit board, electronicparts, and the like and makes them resources.

Such waste mounting substrates have difficulty in separating theelectronic parts from the circuit board, and the mounting substrate isan object in which different materials are intricately integrated,whereby the treatment thereof is difficult. Therefore, reclamationtreatment, combustion treatment, and the like are common.

In this treatment system, waste mounting substrates are thrown into thehermetic container. To raise temperature increase efficiency, heating tosuch a temperature that the resins are not oxidized so much under normalpressure or increased pressure, and then pressure reduction areperformed. This is because thermal conductivity in the hermetic chamberbecomes lower under reduced pressure.

The resins are thermally decomposed (vaporized, liquefied, orcarbonized) selectively as described above, and gases produced by thedecomposition are recovered.

When the component resins of the mounting substrate are treated, toraise temperature increase efficiency in the hermetic container, themounting substrate which is the object to be treated is heated whilepressure and oxygen concentration are regulated by the exhaust system,after being heated to a temperature (200° C.) at which the resins arenot oxidized so much. In this case, the component resins are thermallydecomposed selectively at a temperature corresponding to the degree ofvacuum. As the degree of vacuum becomes higher, the resins are thermallydecomposed at a lower temperature, and thus the hermetic reducedpressure container is never damaged.

The package resins of the electronic parts are also thermally decomposedand become very fragile, whereby the separation from elements in thepackage becomes easy.

Gases produced by the thermal decomposition of resins are recovered by aplurality of recovery devices according to the kinds of the producedgases. For example, hydrogen gas may be recovered by a substance whichadsorbs this gas, and chlorine gas may be recovered as iron chloride bybeing brought into contact with iron heated to a high temperature.

Incidentally, exhaust gas and the like may be made innoxious byhigh-temperature combustion. Moreover, the temperature, pressure, andoxygen concentration in the hermetic container are regulated accordingto metals to be recovered (See FIG. 13, FIG. 18, FIG. 19, FIG. 29, andFIG. 30), and an alloy (for example, a Pb—Sn alloy) bonding the circuitboard and the electronic parts is vaporized. It is desirable toselectively vaporize an alloy depending on its vapor pressure andseparate it in terms of recycling.

If the alloy bonding the circuit board and the electronic parts isvaporized, the electronic parts are separated from the circuit board.

Not only the bonding alloy bonding the circuit board and the electronicparts but also various kinds of metals such as Zn, Sb, Au, Pt, Ni, Cr,Cu, Al, Mo, W, and Ta contained in the mounting substrate may bevaporized, and thereby separated and recovered. The metals can berecovered in a metallic state without turning into oxides, and thus theutility value thereof is high.

At the time of the vaporization of the solder alloy, in order to raisetemperature increase efficiency, after being heated to a temperature(for example, about 200° C.) at which the solder alloy is not oxidizedso much, the solder alloy may be heated further (for example, to about400° C.) while the pressure in the hermetic container is reduced by theexhaust means, and condensed by the condensing means provided midway ina recovery route.

According to this system, the solder alloy of the mounting substrate isremoved completely as shown in FIG. 17, and solder at lead terminalportions in the IC, the LSI, the resistor, the capacitor, and the likeis also removed completely. Therefore, the electronic parts can beremoved from the board, and in addition the recycling of the circuitboard and electronic parts can be facilitated, and their values can beraised.

The component resins of the mounting substrate are vaporized,carbonized, or become an intermediate product, and thus can beeffectively used.

The component metals of the solder alloy are vaporized according to thedegree of vacuum in the hermetic container, and as the degree of vacuumbecomes higher, the metals are vaporized at a lower temperature, wherebya furnace wall and the like of the treatment apparatus are not damaged.

If the mounting substrate is subjected to reclamation treatment, noxiousmetals such as Pb and Sb in the solder alloy melt due to acid rain andthe like to thereby contaminate soil and rivers. Most of resins are notdecomposed naturally and remains semipermanently, which causes shortageof treatment plants and problems in terms of environmental protection.The treatment system can solve these problems.

Moreover, various kinds of metals contained in the circuit board and theelectronic parts can be separated, recovered, and recycled. These metalsinclude metals having a possibility of being exhausted and scarce metalsthe elements of which exist very little in the earth crust.Consequently, the recovery of these metals contributes to the solutionof resources and energy problems which mass consumption societyconfronts at present.

EXAMPLE 15

Next, a circuit board in which copper foil and resins are laminated willbe taken up as the object to be treated, and the treatment systemthereof will be explained.

The circuit board may be a so-called copper laminated sheet, a flexibleboard, or a TAB (Tape Automated Bonding) film carrier. Cut portions ofthe copper laminated sheet produced in the fabrication process ofcircuit boards may be treated. Moreover, as explained above, the circuitboard after the electronic parts and the bonding alloy are separatedfrom the mounting substrate may be treated.

Although the circuit board is explained here as an example, any objecthaving copper and resins as its components can be treated in the samemanner.

The separation of the solder alloy and the electronic parts from themounting substrate is similar to that described above. The thermaldecomposition of the component resins of the mounting substrate is alsothe same as above. A part of the resins may contain paper. This appliesto other portions.

In order to separate the copper foil and the resins, this treatmentsystem heats the circuit board under a reduced pressure condition or anon-oxidation condition to thermally decompose the component resins ofthe circuit board into gas, oil, carbides, and the like. The copper foilis recovered as almost pure metal. Impurities such as carbides adheringto copper may be treated by a method such as cleaning, vibration,rotation with fine sand, or the like as required. It is recommended thatthe treatment apparatus be used as this apparatus.

FIG. 23 is a diagram schematically showing a circuit board 2300 which isthe object to be treated. The circuit board 2300 is a two-layered sheet,copper foil 2301 and resins 2302 are laminated integrally.

The circuit board 2300 is introduced into the hermetic chamber, and theresins 2302 are thermally decomposed (vaporized, liquefied, orcarbonized) selectively in the hermetic container where the temperature,pressure, and oxygen concentration are regulated so that the copper 2301is not substantially oxidized. It is suitable to recover gases producedby the decomposition of the resins 2302 by the exhaust gas treatmentsystem or the like.

On this occasion, it is also suitable to heat the object to be treatedto a temperature (for example, 200° C.) at which the resins 2302 are notoxidized so much, then reduce pressure or reduce oxygen concentrationpartial pressure, and then increase temperature (for example, to 400° C.to 650° C.), which resulting in a rise in temperature increaseefficiency.

FIG. 24 is a diagram schematically showing the circuit board 2300 afterthe component resins are thermally decomposed. Most of resins remain ascarbides.

In this state, the carbonized resins 2302 may be separated mechanically.

If the temperature is increased to a temperature fifty or sixty degreeshigher than the melting point of copper while the pressure or the oxygenconcentration in the hermetic container is regulated, the copper 2301 ina liquid state turns into granular copper 2301 b by surface free energy(surface tension) (FIG. 25). If cooling is performed in this state, theseparation and recovery of copper becomes easier. For example, themelting point of copper at 760 Torr is 1080° C., and copper can becollected in a granular form by increasing the temperature in thehermetic container to about 1150° C. (in the case of 760 Torr).

The copper foil can be recovered with only tiny oxidation taking placeby heating the circuit board under reduced pressure or in anon-oxidizing atmosphere as described above. Incidentally, impuritiessuch as carbides and the like adhering to the surface can be removed bycleaning or the like as required.

As explained above, according to the treatment system, copper can beseparated and recovered in a metallic state from an object in whichresins and copper are integrated. Moreover, the resins can be recoveredas oil and carbides.

EXAMPLE 16

Next, resin-coated aluminum foil in which aluminum foil and resins arelaminated will be taken up as the object to be treated, and thetreatment system thereof will be explained.

Such resin-coated aluminum foil is widely used, for example, for bagsfor potato chips, packing receptacles for retort pouch food such ascurry, packing receptacles for food and medical supplies, heatinsulating materials, and the like.

The treatment of such resin-coated aluminum foil is difficult becauseresins and aluminum foil are integrated, and thus the resin-coatedaluminum foil is treated by reclamation or combustion. In the case ofcombustion treatment, aluminum turns into oxides, and its value asresources sharply drops.

Enormous energy is consumed in refining aluminum, and hence it is awaste of energy not to recycle aluminum.

Herein, the component resins are thermally decomposed (vaporized,liquefied, or carbonized) selectively while the oxidation state ofaluminum is substantially maintained by heating the resin-coatedaluminum foil in the hermetic chamber where the oxygen concentration isregulated. Namely, to separate the aluminum foil and the resinsefficiently, the resin-coated aluminum foil is heated under a reducedpressure condition or a non-oxidation condition, and the resins aredecomposed into gas, oil, carbides, and the like, and recovered. Thealuminum foil is recovered as almost pure metal. Impurities such ascarbides adhering to aluminum may be treated by a method such ascleaning, vibration, rotation with fine sand, or the like as required.

To raise temperature increase efficiency, this treatment system heatsthe resin-coated aluminum foil to a temperature at which the resin isnot oxidized so much, then reduces pressure or reduces oxygen partialpressure, then increases temperature, and consequently decomposesresinous portions into gas, oil, carbides, and the like and recoversthem. The aluminum foil is separated as almost pure metal from theresins.

FIG. 26 is a diagram schematically showing a resin-coated aluminum foil2600. Resins 2601 and aluminum foil 2602 are integrated.

First, the resin-coated aluminum foil 2600 which is the object to betreated is put into the treatment apparatus.

Then, to raise the temperature increase efficiency of the hermeticcontainer, after being heated to a temperature (for example, 200° C.) atwhich the resins 2601 are not oxidized much, the resin-coated aluminumfoil 2600 is heated to 400° C. to 650° C. while temperature and pressureconditions are controlled (See FIG. 18, FIG. 19, FIG. 29, and FIG. 30).

The thermal decomposition of component resins is insufficient attemperatures lower than 400° C., whereas the aluminum foil melts attemperature higher than 650° C., and thus the above temperature range isset.

It is more preferable to thermally decompose the resins selectively at aheating temperature of 550° C. to 650° C. under a pressure not more than10⁻² Torr (or in a non-oxidizing atmosphere).

FIG. 27 is a diagram schematically showing the state of the resin-coatedaluminum foil after the component resins 2601 are thermally decomposedselectively, in which carbides 2602 b which are thermal decompositionproducts of the resins adhere to the aluminum foil 2601 in a metallicstate. In this state, the carbides 2602 easily peel off the aluminumfoil by only soft touch. Therefore, the aluminum foil can be recoveredeasily in a metallic state (See FIG. 28).

Gases produced by the thermal decomposition of resins and emitted arerecovered by a plurality of recovery devices according to the kinds ofgases. A catalyst may be used. For example, it is recommended thathydrogen gas be recovered by being adsorbed by a hydrogen gas adsorbingsubstance. Chlorine gas may be trapped by an alkaline solution such asNaOH to be neutralized, or may be recovered as iron chlorine by beingbrought into contact with iron heated to a high temperature.

Incidentally, exhaust gas such as unrecovered gases may be madeinnoxious by high-temperature combustion. A part of the resins arerecovered as carbides or oil. Generally, component resins ofresin-coated aluminum foil are thermoplastic resins, and the majoritythereof can be vaporized or liquefied, and then recovered. Carbides ofthe component resins can be easily separated from the aluminum foil.Aluminum maintains its metal properties.

Aluminum can be recovered with only tiny oxidation taking place byheating the resin-coated aluminum foil under reduced pressure or in anon-oxidizing atmosphere as described above. Incidentally, impuritiessuch as carbides and the like adhering to the surface can be removed bycleaning or the like as required.

EXAMPLE 17

FIG. 31 is a diagram roughly showing an example of the treatmentapparatus.

FIG. 32 is a diagram schematically showing the structure of thetreatment apparatus illustrated in FIG. 31.

This treatment apparatus 10 includes a thermal decomposition furnace 20which is a first thermal decomposition means for thermally decomposingan object to be treated containing resins and metals at a firsttemperature, a gas decomposing device 30, connected to the thermaldecomposition furnace 2, for reforming or thermally decomposing agaseous emission produced from the object to be treated at a secondtemperature such that dioxins are decomposed, a cooling tower 40 whichis connected to the gas decomposing device 30 and is a cooling means forcooling the gaseous emission to a third temperature so that a rise inthe concentration of dioxins contained in the gaseous emission reformedat the second temperature, a reduced pressure heating furnace 50 forheating a residue resulting from the thermal decomposition of the objectto be treated, solids separated from the gaseous emission, and the likeunder reduced pressure so that a metal contained in the residue arevaporized, and a recovery chamber 60 for condensing the metal vaporizedfrom the residue.

Namely, the treatment apparatus introduces the object to be treatedcontaining resins and metals into the thermal decomposition furnace,thermally decompose it, treats a gaseous emission from the object to betreated by a gaseous emission treatment system mainly composed of thegas decomposing device and a cooling tower to make it innoxious and toturn it into clean fuel gas, and introduces a thermally decomposedresidue of the object to be treated which has emitted the gaseousemission into the reduced pressure heating furnace to separate andrecover a metal.

The thermal decomposition furnace 20 is to thermally decompose theobject to be treated at the first temperature such that the object to betreated is thermally decomposed under controlled oxygen concentration,and extracts a gaseous emission, for example, from shredder dust, wastecircuit boards, and the like. The gaseous emission is basically composedof emission gas, but the case where the gaseous emission contains solidfine particles, liquid fine particles mixed in the emission gas is notexcluded.

FIG. 33 is a diagram schematically showing an example of the structureof the thermal decomposition furnace 20. The thermal decompositionfurnace 20 is composed of a thermal decomposition chamber 21 forthermally decomposing the object to be treated and a combustion chamber22 for heating the thermal decomposition chamber 21, and combusts fuelgas introduced from a fuel gas pipe 23 in a combustion chamber 24 toheat the interior of the thermal decomposition chamber 21 by thiscombustion heat.

A temperature regulating means and an oxygen concentration regulatingmeans which are not illustrated are provided in the thermaldecomposition furnace 20 to maintain the interior of the thermaldecomposition chamber 21 at the first temperature, and to regulateoxygen concentration so that thermal decomposition is performed in areducing atmosphere.

It is recommended to use a heating means and a temperature measuringmeans as the temperature regulating means for regulating the thermaldecomposition furnace 20 at the first temperature. It is suitable toselect the heating means from various kinds of heating such asconvection heating, radiation heating, and the like as required or usethem in combination as the heating means. For example, resistanceheating by a sheathed heater, or the like may be used, or gas, heavyoil, light oil, or the like may be combusted outside the chamber.Moreover, gases emitted from the resins of the object to be treated areturned into fuel gas after being reformed, made innoxious, orneutralized, and may be reused as a heat source of the treatmentapparatus. Furthermore, it is suitable to feed the clean fuel gas, forexample, obtained as described above into a gas turbine generator,convert it to electric power, and to use this electric power for theoperation of the treatment apparatus, including the thermaldecomposition furnace 20.

The use of various kinds of temperature sensors as the temperaturemeasuring means is recommended. It is recommended that the firsttemperature be set so that the resins of the object to be treated arethermally decomposed and that the metals of the object to be treated areoxidized as little as possible, but it is more preferable to maintainthe thermal decomposition furnace 20 on a reducing condition toeradicate production sources of dioxins at many stages as will bedescribed later. For example, by thermally decomposing aromatic serieshydrocarbon compounds containing chlorine under a reducing condition,chlorine contained in the aromatic series hydrocarbon compounds isdecomposed into HCl and the like. Accordingly, the production of dioxinsis suppressed.

This thermal decomposition furnace 20 thermally decomposes the object tobe treated in the temperature range of about 25° C. to about 60° C., andmore preferably in the range of about 400° C. to about 550° C. The firsttemperature may be regulated as required according to the property,structure, and the like of the object to be treated. The setting of thefirst temperature of the thermal decomposition furnace 20 at arelatively low temperature can prevent the vaporization of heavy metalsand the like of the object to be treated, leading to more efficientseparation and recovery in the reduced pressure heating furnace 50 atthe subsequent stage. A load on the thermal decomposition furnace 20 isreduced, and thus its life can be lengthened, resulting in a reductionin treatment costs. Incidentally, the gaseous emission treatment systemmay also treat the gaseous emission from the reduced pressure heatingfurnace. The reduced pressure heating furnace may be used as the thermaldecomposition furnace.

As the oxygen concentration regulating means, an oxygen concentrationsensor which is an oxygen concentration measuring means and a carriergas introduction system may be used. Although the thermal decompositionfurnace 20 is structured separately from the reduced pressure heatingfurnace in the example shown in FIG. 31, the first hermetic chamber 102of the treatment apparatus shown in FIG. 1 and FIG. 2, for example, maybe used as the thermal decomposition furnace.

As the oxygen concentration sensor, for example, a so-called zirconiasensor using zirconia (zirconium oxide) may be used, or the absorptionof CO and CO₂, for example, may be measured by infrared spectroscopy.Besides, GC-MS may be used. It is suitable that the oxygen concentrationsensor is selected from them as required or they are used in combinationas the oxygen concentration sensor.

A rare gas such as Ar or the like may be used as a carrier gas. Thiscarrier gas can not only regulate the oxygen concentration in thethermal decomposition furnace 20 but also lead gases efficiently to thegas decomposing device 30. Moreover, the oxygen concentration regulatingmeans may serve also as a pressure regulating means.

The thermal decomposition furnace 20 is required only to thermallydecompose the object to be treated under controlled oxygenconcentration, and thus a rotary kiln, for example, may be used.

A shredder 25 may be provided at a stage prior to the thermaldecomposition furnace 20 (See FIG. 40). The object to be treated broughtin from the outside of the apparatus may be introduced into the thermaldecomposition furnace 20 after being shredded by the shredder andsegregated, or may be introduced into the thermal decomposition furnacewithout being shredded. When the object to be treated is a waste circuitboard, it is suitable to introduce it into the thermal decompositionfurnace 20 without shredding it.

It is recommended that temperature and oxygen concentration conditionsin the thermal decomposition furnace 20 into which the object to betreated is introduced be regulated so that the metals in the object tobe treated are oxidized as little as possible and so that chlorine whichhas combined with organic compounds on the occasion of thermaldecomposition of the resins is made inorganic as much as possible. Thetemperature and oxygen concentration conditions may be set previously,or may be controlled by feeding back measured values of temperature andoxygen concentration to the heating means, the oxygen concentrationregulating means, and the like. When the oxygen concentration needs tobe measured, the use of a zirconia sensor or the like is recommended.

The pressure in the thermal decomposition chamber 21 of the thermaldecomposition furnace 20 may be controlled. If the pressure in thethermal decomposition chamber 21 is reduced, for example, the oxygenconcentration lowers, whereby the object to be treated is not abruptlyoxidized by heating. A large quantity of gases produced by decompositionare generated from the resins by heating, but generally resins hardlygenerate oxygen even if they are decomposed. Moreover, decompositionproducts of the resins are easily vaporized.

Meanwhile, if the pressure is reduced, the thermal conductivity in thethermal decomposition chamber 21 lowers. But, if a non-oxidizingatmosphere is maintained in the thermal decomposition furnace 20, theobject to be treated is not oxidized even under atmospheric pressure orunder increased pressure. Therefore, if the non-oxidizing atmosphere ismaintained in the thermal decomposition chamber 21, pressurization ispossible, resulting in a rise in the thermal conductivity in the system.

The gaseous emission from the object to be treated is introduced intothe gas decomposing device 30 through a pipe. In the treatment apparatus10 illustrated in FIG. 31, a cyclone separator 29 for separating a solidemission such as dust in the gaseous emission is placed between thethermal decomposition furnace 20 and the gas decomposing device 30. Thiscyclone separator 29 may be provided as required.

The gas decomposing device 30 thermally decomposes or reforms thegaseous emission from the object to be treated at a second temperaturehigher than the first temperature, where thermal decomposition orreforming means that hydrocarbon compounds contained in the gaseousemission from the object to be treated are changed into lower-molecularhydrogen, methane, carbon monoxide, and the like. Moreover,hydroreforming or the like may be performed. it is suitable in terms ofthe eradication of production sources of dioxins to maintain the insideof the system on a reducing condition as described above. If a reducingatmosphere is maintained in the gas decomposing device 30, a smallquantity of air may be introduced into the gas decomposing device 30. Inaddition to thermal decomposition, catalytic cracking by the use of acatalyst may be performed in the gas decomposing device 30. As acatalyst, a metal such as Pt or Re may be used being supported by asolid acid such as alumina silica or zeolite (aluminosilicate).

By providing the gas decomposing device 30 separately from the thermaldecomposition furnace 20, the gaseous emission from the object to betreated can be treated at the second temperature higher then the firsttemperature, which makes it possible to effectively reform the gaseousemission and make chlorine inorganic.

It is desirable that the gas decomposing device 30 keep conditions suchthat dioxins which directly or indirectly originate in the object to betreated are decomposed as much as possible. A considerable amount ofdioxins can be decomposed, for example, by setting the secondtemperature at about 800° C. Furthermore, dioxins can be decomposed moreeffectively by setting the second temperature at 1000° C. or higher, andmore preferably at 1200° C. or higher. This gas decomposing device 30 isset at the second temperature such that dioxins are decomposed, andhence the thermal decomposition of hydrocarbon in the gaseous emissionoccurs simultaneously at the second temperature.

Hydrocarbon compounds contained in the gaseous emission from the objectto be treated are made lower-molecular and changed into hydrogen,methane, carbon monoxide, and the like by being reformed and thermallydecomposed in the gas decomposing device 30.

When dioxins are contained in the gaseous emission, most of the dioxinsare decomposed. Moreover, organic chlorine is made inorganic, and therecomposition of dioxins is suppressed.

FIG. 34 schematically shows examples of the structure of the gasdecomposing device 30.

The gas decomposing device illustrated in FIG. 34( a) forms such atemperature condition that the gaseous emission is thermally decomposedand reformed and that a reducing atmosphere and dioxins are decomposedby introducing the gaseous emission from the thermal decompositionfurnace 20 and a small quantity of air into a chamber filled with cokes.

The gas decomposing device illustrated in FIG. 34( b) is structured toheat the chamber to such a temperature that dioxins are decomposed bycombusting fuel gas and air, and introduce the gaseous emission from thethermal decomposition furnace 20 into this chamber, and thermallydecompose and reform the gaseous emission.

A catalytic cracking means such as a catalyst as described above may beprovided in the chamber in the gas decomposing device 30.

A temperature regulating means and an oxygen concentration measuringmeans for regulating the temperature and oxygen concentration in thechamber may be provided in the gas decomposing device 30 as required. Asthe oxygen concentration regulating means, such oxygen concentrationsensor and carrier gas introduction system as described above may beused. Moreover, a hydrogen gas reservoir may be connected, or areservoir for an inert gas such as Ar may be connected.

As described above, the gaseous emission contained in the gaseousemission from the object to be treated is made lower-molecular by thegas decomposing device 30 or a second thermal decomposition means andchanged into hydrogen, methane, carbon monoxide, and the like.

The gaseous emission thermally decomposed and reformed in the gasdecomposing means 30 is introduced into the cooling tower 40.

The cooling tower 40 is placed to connect with the gas decomposingdevice 30, and cools the gaseous emission reformed or thermallydecomposed at the second temperature to a third temperature so that arise in the concentration of dioxins in the gaseous emission issuppressed.

Namely, the concentration of dioxins in the gaseous emission reformed orthermally decomposed at the second temperature in the gas decomposingdevice 30 or the second thermal decomposition means is extremely low,since the second temperature is a temperature such that the dioxins aredecomposed and chlorine in hydrocarbon compounds decomposed or reformedat this temperature is made inorganic by a reducing atmosphere.Accordingly, in order to prevent the production and recomposition ofdioxins from this state, the gaseous emission is cooled to the thirdtemperature so that a rise in the concentration of dioxins in thegaseous emission is suppressed as much as possible. The thirdtemperature may be set at a temperature such that no production reactionof dioxins occurs.

The production and recomposition of dioxins can be suppressed, forexample, by cooling the gaseous emission in which dioxins are alreadydecomposed (the temperature of which is required to be higher than atemperature such that dioxins are decomposed even if it is not the sameas the second temperature in the gas decomposing device 30) to 150° C.or lower, more preferably 100° C. or lower, still more preferably 50° C.or lower, and most preferably 35° C. or lower.

On this occasion, it is desirable to cool the gaseous emission to thethird temperature in the possible shortest time. This is because dioxinsare easily produced and recomposed in the range of about 200° C. toabout 400° C., and thus the concentration of dioxins in the gaseousemission can be held down more effectively by cooling the gaseousemission to the third temperature to shorten the retention time of thegaseous emission in the temperature range in which dioxins are easilyproduced and recomposed as much as possible.

Therefore, it is desirable to perform cooling of the gaseous emission inthe cooling tower 40 rapidly, preferably within about ten seconds.

As an example of such a cooling tower 40, it is suitable to performcontact cooling by directly jetting a refrigerant such as water orcooling oil to the gaseous emission. On this occasion, if alkalinepowder such as lime powder or the like is jetted to the gaseousemission, the gaseous emission is neutralized. Moreover, HCl in thegaseous emission, for example, is spread over the surfaces of solids bytouching the lime powder, which can also suppress the production andrecomposition of dioxins.

FIG. 35 schematically shows examples of the structure of the coolingtower 40.

FIG. 35( a) shows structure in which the gaseous emission introducedfrom the decomposing device 30 is rectified and cooled to the thirdtemperature by directly jetting a refrigerant such as cooling water orcooling oil thereto. FIG. 35( b) shows structure in which productionresources of dioxins are removed from the gaseous emission byneutralizing the gaseous emission by jetting a neutralizer such as limepowder together with a refrigerant thereto and by fixing chlorine in thegaseous emission.

In the cooling tower 40, temperature sensors not illustrated areprovided in a gaseous emission introduction section and a cooling gasexhaust section, and an introduced gaseous emission cooling rate controlmeans, for example, a refrigerant flow rate and temperature regulatingmeans is provided, whereby the cooling rate of the gaseous emission iscontrolled so that the production and recomposition of dioxins aresuppressed.

As described above, the gaseous emission emitted from the object to betreated in the thermal decomposition furnace 20 is changed intohydrogen, methane, carbon monoxide, and the like by being thermallydecomposed or reformed at a temperature such that dioxins are decomposedin the gas decomposing device 30 and being cooled so that the productionand recomposition of dioxins do not occur in the cooling tower 40, andbesides the concentration of dioxins in the gaseous emission is sharplylowered.

As described above, in the treatment apparatus, the generation ofdioxins can be suppressed by treating the decomposition of the object tobe treated and the decomposition of the gaseous emission from the objectto be treated at plural stages in the thermal decomposition furnace 20and the gas decomposing device 30 and by maintaining a reducingatmosphere in such decomposition means.

The concentration of dioxins in the gaseous emission could be lowered to0.1 TEQng/Nm³ to 0.5 TEQng/Nm³ by setting the second temperature at 800°C. and the third temperature at 150° C.

Moreover, the concentration of dioxins in the gaseous emission could belowered to 0.1 TEQng/Nm³ or lower by setting the second temperature at1150° C. and the third temperature at 50° C.

The gaseous emission cooled in the cooing tower 40 may be cleaned anddesulfurized as required.

Furthermore, the gaseous emission cooled in the cooling tower 40 may beintroduced into a neutralization reaction filter means such as a bagfilter. Between the cooling tower 40 and the neutralization reactionfilter means, slacked lime, filter aid (for example, particles with highvoids such as zeolite or activated carbon, Teshisorb, Shirasu balloons)or the like may be blown into a current of the gaseous emission by a dryventuri or the like.

FIG. 36 is a diagram showing a part of the structure of a gaseousemission treatment system in which a bag filter 70 is connected to astage subsequent to the cooling tower 40.

A solid emission such as heavy metal fine particles condensed in thecooling tower 40 and solids let out from the bag filter 70 can beseparated and recovered by being introduced into the reduced pressureheating furnace 50 and treated even when metals such as lead, tin,arsenic, and cadmium are contained in the gaseous emission.

The gaseous emission emitted from the object to be treated which hasbeen treated as above may be used as a heat source of heating in thethermal decomposition furnace 20 or may be supplied to a gas turbinegenerator to obtain electric power. Moreover, this electric power may beused for a heat source of the treatment apparatus and the like.

Meanwhile, a thermally decomposed residue of the object to be treatedwhich has emitted the gaseous emission in the thermal decompositionfurnace 20 is introduced into the pressure reduced heating furnace 50.Since most of organic components of the object to be treated aredecomposed in the thermal decomposition furnace 20 which is the firstthermal decomposition means, the thermally decomposed residue is mainlycomposed of metals and carbides or glass.

The reduced pressure heating furnace 50 for separating and recoveringmetals from this thermally decomposed residue which is the object to betreated is composed of a purge chamber 51, a first hermetic chamber 52,and a cooling chamber 53, and the respective chambers are partitioned byopenable and closeable partitions 54. The thermal decomposition furnace20 and the first hermetic chamber of the reduced pressure heatingfurnace 50 may be connected via the purge chamber 51.

In the reduced pressure heating furnace 50 of the treatment apparatusillustrated in FIG. 31, the object to be treated is introduced to thepurge chamber 51 after a partition 54 a is opened. The partition 54 a isclosed and the purge chamber 51 is roughly evacuated by an exhaustsystem not illustrated, and thereafter a partition 54 b is opened, andthe object to be treated is moved to the first hermetic chamber 52.

The partition 54 b is closed, and the pressure and temperature in thefirst hermetic chamber 52 are controlled so that a metal in the objectto be treated is vaporized under reduced pressure. The metal vaporizedfrom the object to be treated is condensed and recovered in the recoverychamber 60. The structure of this recovery chamber may be similar tothat illustrated in FIG. 8, FIG. 9, FIG. 10, FIG. 11, and FIG. 12, forexample. The numeral 55 denotes an exhaust system. Exhaust gas from anexhaust gas treatment system of the thermal decomposition furnace 50 maybe introduced to the decomposing device 30.

After a desired metal is vaporized, a partition 54 c between thehermetic chamber and the cooling chamber 53 in which the pressure isreduced by an exhaust system not illustrated is opened, and the objectto be treated is moved to the cooling chamber 53.

The partition 54 c is closed, and the object to be treated is cooled.When the object to be treated gets into a stable state even in theatmosphere, the cooling chamber 53 is made to leak, a partition 54 d isopened, and the object to be treated is taken out.

The contents of the object to be treated are composed of carbides andmetals not vaporized, and these metals can be easily separated from thecarbides.

As described above, herein, the object to be treated having resins andmetals can be recycled to a high level, and moreover, the generation ofdioxins can be prevented.

EXAMPLE 18

FIG. 37 is a diagram roughly showing another example of the treatmentapparatus.

FIG. 38 is a diagram schematically showing the structure of thetreatment apparatus illustrated in FIG. 37. In this treatment apparatus,acidic constituents in the gaseous emission cooled in the cooling tower40 are neutralized in the neutralizing and cleaning tower 61 anddesulfurized in a desulfurizing tower 62 so as to be utilized as cleanfuel gas. This fuel gas is sent to a combustion chamber 23 of thethermal decomposition furnace 20 and used as heating fuel for thethermal decomposition furnace, or filtered by an activated carbon filter63 and then sent to a gas turbine generator 64 to be converted intoelectric power. Exhaust gas resulting from the heating of the thermaldecomposition furnace 20 and exhaust gas from the gas turbine generator64 are released into the atmosphere from a chimney 66 after componentsand concentration are monitored by a GC-MS or the like and safety isconfirmed.

The adoption of such structure enables the treatment apparatus to treatthe object to be treated more efficiently.

The running cost of the apparatus can be kept down to a low level, forexample, by neutralizing and cleaning the gaseous emission which is madeinnoxious and utilizing it as clean fuel gas for the heating of thethermal decomposition furnace, and in addition by operating the reducedpressure heating furnace by electric power obtained by the gas generatoror selling the electric power.

The first temperature in the first thermal decomposition means is as lowas 600° C. or lower, and thus the life of the thermal decompositionfurnace is long, leading to easy maintenance.

FIG. 39 is a diagram showing an example in which a treatment method isapplied to wastes treatment. Namely, wastes are thermally decomposed, agaseous emission from the wastes is turned into clean fuel gas by thegaseous emission treatment system, and a thermally decomposed residue isintroduced to the reduced pressure heating furnace and can be recoveredas heavy metals, useful metals, activated carbon, and the like.

FIG. 40 is a diagram schematically showing an example of the structureof shredding equipment which can be provided at a stage prior to thetreatment apparatus. Shredding equipment for treating waste automobilesis illustrated here.

Waste automobiles are shredded by a shredder and classified into aferrous group, a non-ferrous group, a non-metallic group, and the likeby magnetism, wind force, or the like. Such classified residues areshredder dust. The shredder dust includes various kinds of metalsincluding resins (including fiber and paper), glass, and heavy metals.By adopting the aforesaid structure, such shredder dust for which thetreatment technology has not been hitherto established can be alsotreated safely and efficiently.

Shredder dust is thrown into the thermal decomposition furnace 20 andthermally decomposed at 400° C. to 500° C., and a gaseous emissionemitted from resin components, organic components, or the like of theshredder dust is led to the gas decomposing device 30 and thermallydecomposed at the second temperature of 1100° C. or higher (morepreferably, 1150° C. or higher) so as to decompose noxious substancessuch as dioxins and make them innoxious. Immediately after this, it israpidly cooled within ten seconds in the cooling tower 40 in which thethird temperature is set at 100° C. or lower (more preferably, 50° C. orlower), whereby the production of dioxins can be suppressed to 0.1TEQng/Nm³ or lower. Clean fuel gas can be obtained by removing cyanides,sulfides, nitrides, and the like from the gaseous emission from theobject to be treated which is treated as above by the gas cleaning(neutralizing) device and the desulfurizing device.

This fuel gas is utilized as a heating source for the thermaldecomposition furnace 20, and converted into electric power by electricpower generation by the gas turbine generator to thereby operate thereduced pressure heating furnace 50.

A thermally decomposed residue of the object to be treated is introducedto the reduced pressure heating furnace 50 and heated under a reducedpressure of 10⁻¹ Torr to 10⁻³ Torr, whereby metals such as Pb, Sb, As,Cd, Sn, and Zn can be separated and recovered at a yield of 99% or more.Pb, Sb, As, Cd, Sn, and Zn in the object to be treated which has beentreated in the reduced pressure heating furnace 50 can be reduced to thelevel of 0.1 ppm.

A ferrous group remaining in the object to be treated which has beentreated in the reduced pressure heating furnace 50 is separated andrecovered by gravity concentration, an electric magnet, and the like,and finally innoxious and high-purity carbides can be obtained. Thesecarbides may be used in the activated carbon filter 63, or may beutilized for an effective soil conditioner and the like.

As described above, herein, household electrical products, automobiles,precision equipment, and the like, or shredder dust of these wastes arethermally decomposed while oxygen concentration is controlled, andtreated in the gaseous emission treatment system and the thermallydecomposed resin treatment system, whereby the gaseous emission can beturned into clean fuel gas by noxious substances such as dioxins thereinbeing decomposed and made innoxious. This fuel gas can be led to thecombustion chamber of the thermal decomposition furnace or the like andused as a heating source. Besides, it is possible to generateelectricity by using this fuel gas. Compared with a hydroelectric powergeneration method which has difficulty in supplying electric powerconstantly since water is in short supply in the dry season, shredderdust is abundant and inexpensive resources, and it is possible togenerate electricity very efficiently by the use of the treatmentapparatus. Moreover, the treatment apparatus has module structure, andhence can cope with an extensive scale from a small scale to a largescale and various uses.

Meanwhile, from the thermally decomposed residue, various kinds ofmetals can be separated and recovered in a high-purity metallic state byheating under vacuum. Carbides also can be utilized effectively sinceheavy metals are removed therefrom. Compared with a melting furnace, thereduced pressure heating furnace is smaller in size, wherebyinstallation costs and installation space can be decreased, which makesit possible to efficiently cope with wastes treatment on a municipalscale.

As described above, reusable substances can be recovered in ahigh-purity state from a large quantity of wastes, which contain noxioussubstances or source materials thereof and produce noxious substancesincluding dioxins if combusted, without releasing noxious substances,heavy metals, and the like into the environment.

Furthermore, according to the treatment apparatus and the treatmentmethod, circuit boards and various kinds of electronic parts such asICs, resistors, capacitors, and the like can be easily separated fromwaste mounting substrates and the like, and simultaneously solder alloysand the like can be separated and recovered.

First, a mounting substrate is introduced to the thermal decompositionfurnace 20 without being shredded, and then thermally decomposed afterthe first temperature is set at 250° C. to 500° C. On this occasion, thepressure in the thermal decomposition furnace may be reduced. In orderto suppress the generation of noxious substances such as dioxins, agaseous emission produced by the thermal decomposition of the mountingsubstrate is led to the gas decomposing device 30 and decomposed byheating at 800° C. or higher, and thereafter cooled to 100° C. or lowerin the cooling tower 40. A thermally decomposed residue is introduced tothe reduced pressure heating furnace 50, and component metals of asolder alloy are vaporized by reducing the pressure to about 10⁻³ andincreasing the temperature to 350° C. to 700° C. successively.Accordingly, a circuit board and various kinds of electronic parts suchas an IC, a resistor, and a capacitor are separated, and concurrentlymetals such as vaporized lead and the like can be recovered by acohering means provided midway in a recovery route.

The electronic parts and the circuit board can be separated almostcompletely by such a method. Moreover, low-melting metals such asnoxious Pb can be removed almost completely (the level of 0.1 ppm). Theconcentration of noxious substances in a gaseous emission generated fromresinous portions is extremely low, and the concentration of dioxins,for example, can be lowered to the range of 0.1 TEQng/Nm³ to 0.5TEQng/Nm³. The circuit board, from which the electronic parts aredismounted and bonding metals are removed, is carbonized and gets into astate in which copper for wiring is contained. Noxious metals such as Pband Sb are removed from the various electronic parts such as an IC, aresistor, and a capacitor, and the resinous portions such as a moldresin are carbonized and get into a state in which a part of themcontain metals such as Si, Au, Ni, W, and Mo.

Subsequently, the circuit board carbonized and containing copper isfurther heated (1050° C. to 1200° C.) in the reduced pressure heatingfurnace 50, and copper foil is half melted to cohere into a sphericalshape of five or six millimeters.

The performance of such treatment facilitates the separation andrecovery of copper from carbides. This circuit board composed ofcarbides and metallic copper is cleaned by a calcium carbonate aqueoussolution or the like, and thereby high-purity copper can be recovered.

As described above, herein, from a waste mounting substrate, the circuitboard and various kinds of electronic parts can be easily separatedwithout emitting noxious substances and with noxious substances beingremoved, and without manpower. At the same time, various kinds of metalsincluding component metals of the solder alloy can be separated andrecovered by vaporizing them. Moreover, metals not vaporized such ascopper can be recovered at high purity. Herein, reusable substances canbe recovered in a high-purity state from wastes such as mountingsubstrates, for which the effective treatment technology has not beenhitherto established, without releasing noxious substances, heavymetals, and the like into the environment.

EXAMPLE 19

FIG. 41 is a diagram showing another example of the treatment apparatus.In this example, the retort 115 c is connected directly to the exhaustsystem through the third opening 115 d. A space between the thirdopening 115 d and the exhaust system is hermetically sealed by packing115 p. The packing may be made of asbestos, for example. A pipe forconnecting the third opening 115 d and the exhaust system when theretort is inserted into the first opening may be provided in place ofthe packing. The adoption of such structure can prevent a gaseousemission from the object to be treated from entering a space between theretort 115 c and the recovery chamber 115. This is because the pressurein the second hermetic chamber 103 is lower than the pressure inside thespace between the retort 115 c and the recovery chamber 115.

Further, it is suitable to provide a carrier gas introduction system 115n and supply an inert carrier gas such as nitrogen gas to the spacebetween the retort 115 c and the recovery chamber 115. This carrier gasis introduced to the retort 115 c through the second hermetic chamber103, and led to the exhaust system through the third opening 115 d ofthe retort. Thus, the space between the retort 115 c and the recoverychamber 115 is sealed off from the second hermetic chamber 103 bypressure. Since the space between the retort 115 c and the recoverychamber 115 communicates with a space in which the hermetic door 115 bis housed when being open, vaporized substances from the object to betreated can be prevented from condensing at the hermetic door, andparticularly at seal portions 115 q thereof. Moreover, a fitting marginof the retort 115 c and a sleeve 103 s increases by adopting theaforesaid structure, which can prevent the retort 115 c and the sleeve103 s from being locked by engagement, and also can downsize a drivingmeans of the retort 115 c such as the cylinder 23 or make itunnecessary.

FIG. 42 is a diagram showing another example of the structure of thetreatment apparatus. In this example, the third opening 115 d of theretort 115 c is connected to the exhaust system through a pipe 116. Thispipe 116 opens and closes the connection of the exhaust system and theretort by moving up and down. Moreover, the pipe 116 and seal faces 115m of the recovery chamber, and the pipe 116 and the third opening 115 dof the retort 115 c are both hermetically connected by the elasticdeformation of packing 116 q. When the retort 115 c is inserted into thefirst opening 103 b, the third opening 115 d of the retort and theexhaust system are hermetically connected by the pipe 116. When theretort is pulled out and the hermetic door 115 b is closed, the pipe 116is moved to a waiting position by a cylinder 23 b.

Incidentally, in this example, the carrier gas introduction system 115 nincludes a pressure gauge g for detecting the pressure in the spacebetween the retort 115 c and the recovery chamber 115, and controls theflow rate of a carrier gas by opening and closing a valve according tothe detected pressure. For example, it is recommended that the pressurein the second hermetic chamber 103 be detected, and that such regulationthat the pressure in the space between the retort 115 c and the recoverychamber 115 is slightly higher than the above pressure be performed. Bydoing this, the gaseous emission from the object to be treated can beled into the retort even if there is a clearance between the retort 115c and the sleeve 103 s.

Furthermore, in this example, the hermetic door 115 b adopts doublestructure. This hermetic door 115 b is opened and closed by a cylinder.Joints 115 change the force of the cylinder when the door is closedalmost perpendicularly to the pushing direction of the cylinder. Byadopting such structure, packing 115 q are pushed against the recoverychamber more firmly. It is desirable to cool an area on which thepacking 115 q of the hermetic door of the recovery chamber 115 by watercooling or the like.

FIG. 43 is a diagram showing another example of the treatment apparatus.In this example, an open face of the third opening 115 d of the retort115 b and the second open face 115 f are arranged suitably, whereby theinserting operation of the retort 115 c and the connecting operation ofthe retort 115 c and the exhaust system can be performed simultaneously.Wire gauze, a dry filter, or the like may be placed in the aforesaidretort 115 c so as to facilitate the condensation of vaporizedsubstances from the object to be treated. Such a dry filter may be madeof the same material as that of a condensate. For example, when zinc isvaporized from a zinc steel plate, post-treatment after recovery isfacilitated if the dry filter and the retort itself are made of zinc.FIG. 44 and FIG. 45 are diagrams for explaining an example of a guidemechanism for guiding the forward and backward movement of the retort115. FIG. 44 shows a sectional view of the retort 115 c in a directionparallel to the second opening 115 f, and FIG. 45 shows a sectional viewthereof in a direction parallel to the direction of the forward andbackward movement of the retort. In this example, guide rolls 115 g areprovided along the direction of the forward and backward movement of theretort on the inner surface of the recovery chamber 115. Such a guidemechanism can make the forward and backward movement of the retort morecertain. Moreover, this guide roll is made of metal, and takes charge ofa part of heat conduction of the retort 115 c and the recovery chamber115. Thereby, the temperature of the retort can be regulated moreeffectively.

FIG. 46 is a diagram showing the sectional structure of a wet filterprovided in the treatment apparatus.

In an oil film filter 711, oil 711 o for a vacuum pump with small vaporpressure collects inside a casing 711 a, and a lower portion of a cloth711 c the upper and lower openings of which are hermetically fixed tothe casing 711 a is immersed in this oil 711 o. The oil forms a filmalong the surface of the cloth 711 c by capillarity. Dust which has notbeen trapped by the recovery chamber 115 and other filter means istrapped by the oil film of this cloth 711 c.

In the treatment apparatus, it is desirable to provide such an oil filmfilter 711 between the aforesaid recovery chamber 115 and exhaustsystem. This is because vaporized substances which have not beencondensed in the retort 115 and the like and fine particles oncecondensed are prevented from reaching the exhaust system. Thus, theexhaust capability of the vacuum pump can be maintained. In addition,the life of the vacuum pump and a period of time to the next maintenancecan be lengthened.

EXAMPLE 20

Herein, treatment of shredder dust is performed. Automobile shredderdust is prepared as a sample. This sample is composed of the followingsix types of fractions. Incidentally, as for the automobile, MINICA(manufactured by Mitsubishi Motors Corporation) is used.

(1) vinyl chloride (10 wt %)

(2) polypropylene (10 wt %)

(3) polyurethane (10 wt %)

(4) rubber (10 wt %)

(5) polyurethane (10 wt %)

(6) others (50 wt %)

The fraction (6) is press-treated.Such shredder dust is treated by thermal decomposition under normalpressure (600° C. and 800° C.) and thermal decomposition under reducedpressure (600° C. and 800° C.), and the concentration of dioxinscontained in the thermally decomposed residue thereof is measured.

FIG. 47 is a chart for explaining treatment conditions for thermaldecomposition. In the case of 600° C., the shredder dust rises intemperature from normal temperature to 600° C. in two hours, and iscooled after being maintained at 600° C. for two hours and a half. Inthe case of 800° C., the shredder dust rises in temperature from normaltemperature to 800° C. in two hours and a half, and is cooled afterbeing maintained at that temperature for two hours and a quarter.

In the case of cooling in the thermal decomposition under reducedpressure, purge under reduced pressure is applied, while in the case ofcooling in the thermal decomposition under normal pressure, air coolingis performed without the present invention being applied. A thermallydecomposed residue resulting from the thermal decomposition under normalpressure at 800° C. in which dioxins remain, is thermally decomposedfurther at 800° C. under reduced pressure, and the concentration ofdioxins contained in the thermally decomposed residue is measured (thefraction of 800° C. thermal decomposition B in FIG. 48).

FIG. 48 shows the measurement results thereof. PCDDs and PCDFs aremeasured separately, and the sum of them is dioxin concentration (ng/b).Moreover, n.d. (not detected) in FIG. 48 shows that no dioxin isdetected.

As shown above, dioxins in the heated residue can be extremely reduced.Especially, in the thermal decomposition under normal pressure, dioxinsstill remain even after treatment at 800° C., but dioxins can be removedif this residue is retreated under reduced pressure. Although thetreatment example in which the shredder dust is used as the object to betreated is explained above, the same result can be obtained also in thecase of soil, burned ashes, sludge, and the like. Provided is, as wastestreatment equipment, may be a manual system suitable for treatment insmall quantities for general factories or a continuous treatment furnacesuitable for treatment in bulk quantities for a self-governing body andthe like, and combination is possible depending on treatment costs.

Incidentally, herein, heavy metals such as lead, cadmium, mercury, zinccontained in soil can be separated from the soil by vaporizing themunder reduced pressure. The separation and recovery of these heavymetals from the object to be treated can be performed by the aforesaidtreatment apparatus. The concentrations of phosphorus and cyanogen inthe soil also can be lowered to values not more than the environmentalstandard values.

EXAMPLE 21

FIG. 49, FIG. 50, and FIG. 51 are diagrams roughly showing otherexamples of the structure of the treatment apparatus.

In FIG. 49, FIG. 50. and FIG. 51, a dry distillation chamber 701 forthermal decomposition under normal pressure and a vacuum vaporizationchamber 702 for thermal decomposition under reduced pressure areprovided as heat treatment chambers. A cooling chamber 703 for coolingthe heated residue is positioned at a stage subsequent to the abovechambers. These treatment chambers are partitioned by a vacuum door soas to be openable and closeable.

In the structure illustrated in FIG. 49, FIG. 50, and FIG. 51, theobject to be treated such as soil is introduced into the drydistillation heating chamber 701 and thermally decomposed, and thenintroduced into the vacuum vaporization chamber 702, where heavy metalssuch as arsenic, cadmium, lead, and the like are removed byvaporization. The heated residue of the object to be treated isintroduced into the cooling chamber 703 and cooled in an atmospheresimilar to that described above which is organic halide-free and notcapable of producing organic halides. The contents of the system isexhausted by booster pumps 705 and 712 and rotary pumps 706 and 713. Thestructure in which a gaseous emission from the object to be treated istreated by a gas treatment device in the same manner as above is given.The gaseous emission from the dry distillation heating chamber 701 isintroduced into a gas treatment device 714 through a gas cracking device707 and a condenser 708 for condensing and recovering vaporizedsubstances in the gaseous emission. The gaseous emission from the vacuumheating chamber 702 is introduced into the gas treatment device 714through a recovery chamber 709 including the retort 115 c and the oilfilm filter 711. The gas treatment device 714 includes a gas crackingdevice 715, a jet scrubber 716, an activated carbon filter, and anexhaust blower 718. In the example shown in FIG. 51, the gas crackingdevice 715 is omitted in the gas treatment device 714. Moreover, a gascombustion device for combusting the gaseous emission in place of thejet scrubber 716, and an alkali shower for alkali-cleaning the gaseousemission in place of the activated carbon filter 717 may be provided.

In FIG. 49 and FIG. 51, a loading chamber 704 for introducing the objectto be treated to the dry distillation heating chamber 701 and the drydistillation heating chamber are common, but they may be providedseparately. Furthermore, although FIG. 51 shows the structure in whichan oil jet scrubber 708 b is provided as a gas treatment device and oilin the gaseous emission is recovered there, the condenser 708 may beprovided, instead.

EXAMPLE 22

Provided is a vacuum vaporization and recovery device, and in increasingdetail to a high-efficiency vacuum vaporization and recovery device inwhich it is unnecessary to reduce the temperature of a vacuum furnace inrecovering a metal from vaporized substances generated by vacuum heattreatment in the vacuum furnace.

In a conventional vacuum vaporization and recovery device, in recoveringa metal from vaporized substances generated by vacuum heat treatment ina vacuum furnace, it is required to go through the processes of reducingthe temperature in the vacuum furnace, taking out metallic recoveredsubstances, and then increasing the temperature in the furnace again toperform vacuum heat treatment. This is because complete vacuum sealingcan not be obtained since a vaporized metal adheres to a seal portion ofa vacuum door located between the vacuum furnace and a metal recoverydevice, as a result air flows into the vacuum heating furnace at thetime of the recovery of the metal, and thereby recovery operation cannot be performed.

As described above, in the conventional vacuum vaporization and recoverydevice, it is required to cool the vacuum furnace in recoveringvaporized substances, and to increase the temperature in the furnaceagain after the recovery, but there is a disadvantage that the operationof the vacuum furnace needs to be stopped for a long period of time (forexample, four days) for the aforesaid cooling and heating.

Accordingly, a problem to be solved is to provide a vacuum vaporizationand recovery device having no disadvantage such as described above, thatis, enabling continuous operation since it is unnecessary to change thetemperature in the furnace when vaporized substances are recovered, asharp rise in operation efficiency, and advantage in terms of costs.

Another problem is to provide a vacuum vaporization and recovery devicein which there is no possibility that vaporized fine particles reach avacuum valve and a vacuum pump to lower the vacuum hermetic sealingcapability of the vacuum valve or to cause a failure of the vacuum pump.

The aforesaid problems are addressed by a vacuum vaporization andrecovery device in which a cooling and vacuum purge chamber having acooling function is connected to a vacuum furnace via a vacuum door, avaporized substance recovery retort is provided in the cooling andvacuum purge chamber so as to move forward and backward therein, passthrough the vacuum door and fronting the interior of the vacuum furnaceon the occasion of forward movement, and get out of the vacuum purgechamber on the occasion of backward movement, the recovery retort beingattachable to and detachable from a shaft of a cylinder for moving theretort forward and backward.

Furthermore, the aforesaid problems are addressed by a vacuumvaporization and recovery device in which a cooling and vacuum purgechamber is connected to a vacuum furnace via a vacuum door, and in thata vacuum valve and a vacuum pump are connected to the cooling and vacuumpurge chamber via a filter. It is preferable that both a solid filter(dry filter) and a liquid filter (wet filter) are used for the filter inthis case.

An embodiment of the present invention will be explained based on theattached drawings. FIG. 52 is an entire block diagram of an apparatus,and this apparatus is composed of a vacuum furnace 1, a vacuum doubledoor 2 placed at an outlet for vaporized substances, a cooling andvacuum purge chamber 3 connected to the vacuum furnace 1 via the vacuumdouble door 2, a solid-type fine particle recovery filter 4 and aliquid-type fine particle recovery filter 5, and a vacuum valve 6 and avacuum pump 7 which are connected to a gas passage from the cooling andvacuum purge chamber 3.

A recovery retort 21 which is moved forward and backward by theoperation of the insertion cylinder 23 is inserted into the cooling andvacuum purge chamber 3. A vacuum door 32 for vacuum-sealing an openingof an end portion of the cooling and vacuum purge chamber 3 is placed inthe cylinder 23, and a cylinder shaft of a moving cylinder 31 isconnected to the cylinder 23. The recovery retort 21 is pulled out ofthe cooling and vacuum purge chamber 3 with the extension motion of themoving cylinder 31.

FIG. 53 shows the details of the vacuum double door 2 and the coolingand vacuum purge chamber 3, and the vacuum double door 2 is placedbetween the vacuum furnace 1 encircled by a heat insulating material 10and the cooling and vacuum purge chamber 3 provided adjacent thereto.The vacuum double door 2 is a double door in which a heat insulatingvacuum door 12 placed on the vacuum furnace 1 side and a vacuum door 13placed on the opposite side thereto are combined, and it is raised andlowered by the operation of an opening and closing cylinder 15 placed ona door case 14 and hermetically blocks a passage to the cooling andvacuum purge chamber 3 when being lowered. An unrecovered vaporizedsubstance outlet 17 is provided in the cooling and vacuum purge chamber3, and the solid-type fine particle recovery filter 4 is provided in thegas passage extending from the unrecovered vaporized substance outlet17.

The cylindrical recovery retort 21 for recovering metallic vaporizedsubstances is inserted so as to reach the vacuum furnace 1 through thevacuum double door 2 in an open state from the cooling and vacuum purgechamber 3. The recovery retort 21 has an open front end portion frontinga heating portion of the vacuum furnace 1, and vaporized gases producedin the vacuum furnace 1 can get into the recovery retort 21 from thatportion. An opening is provided in a side face of a rear end portion ofthe recovery retort 21, and a metallic net 22 is put up there to enableventilation between the inside and the outside of the retort.Incidentally, it is preferable to provide a heat exchange function bydoubling surrounding walls of the cooling and vacuum purge chamber 3 toallow cooling water to flow between them.

A cylinder shaft 24 of the insertion cylinder 23 for moving the recoveryretort 21 forward from the cooling and vacuum purge chamber 3 into thevacuum furnace 1 is removably engaged with a rear end face of therecovery retort 21. As an engaging means, structure in which anattaching plate 27 having a long hole 26 with a width enough for themovement of the cylinder shaft 24 is attached to the rear end face ofthe recovery retort 21 with a gap 28 between them, whereas an engagingportion 29 with a width larger than that of the long hole 26 is providedat an front end portion of the cylinder shaft 24 is thought.

In this case, if the engaging portion 29 is inserted into the gap 28 andthe cylinder shaft 24 is slid into the long hole 26 while the operationis performed in a state in which the recovery retort 21 is lifted by ahoist or the like, the engaging portion 29 is caught by the edge of thelong hole 26, and thus the cylinder shaft 24 is engaged with the rearend face of the recovery retort 21 via the attaching plate 27.Consequently, the recovery retort 21 can move in a horizontal directionaccompanying the movement of the cylinder shaft 24. Incidentally, thecylinder shaft 24 is covered with a bellows cover 30.

The insertion cylinder 23 is fixed to a cylinder supporting block 33which reciprocates on a frame 18 by the operation of the moving cylinder31 via the vacuum door 32 attached to the insertion cylinder 23, andthereby moves on the frame 18 with the movement of the cylindersupporting block 33. Namely, the cylinder supporting block 33 is placedon a movable carriage 36 having rollers 34 and structured to be movableon a table 35 of the frame 18, and the moving cylinder 31 is placedunder the table 35 in the frame 18 and its cylinder shaft is fixed tothe movable carriage 36.

As shown in FIG. 54, the vacuum door 32 is fixed to a flange portion ofthe insertion cylinder 23, and has a vacuum seal 32 a at a portionthrough which the cylinder shaft 24 is inserted and packing 32 a whichis closely attached to an end portion flange 3 a of the cooling andvacuum purge chamber 3, and thus vacuum-seals the cooling and vacuumpurge chamber 3.

After the closing operation of the vacuum double door 2, the insertioncylinder 23 reaches a rear end portion (the right end in FIG. 53) of theframe 18 at the end of the extension movement of the moving cylinder 31,and the exchange operation of the recovery retorts 21 is performed atthe end of backward movement (hereinafter, this position is referred toas “a first stop point”). The new recovery retort 21 is attached to thecylinder shaft 24 of the insertion cylinder 23, for example, by anengaging means such as described above. When the attaching operation ofthe new recovery retort 21 is completed, the movable carriage 36 ismoved forward (moved leftward in FIG. 53) by the contraction movement ofthe moving cylinder 31.

Following this, the recovery retort 21 gets into the cooling and vacuumpurge chamber 3, and stops and waits at the end of the contractionmovement of the moving cylinder 31.

At this waiting position, the front face of the recovery retort 21 ispositioned just in front of the vacuum double door 2 which blocks up thecooing and vacuum purge chamber 3 at this time (hereinafter, thisposition is referred to as “a second stop point”), and the vacuum door32 is closely attached to the end portion flange 3 a of the cooling andvacuum purge chamber 3 and vacuum-seals it.

Next, the operation of the apparatus structured as above will bedescribed in increasing detail. As described above, when the movablecarriage 36 reaches an end portion of the frame 18 (the first stoppoint) by the extension movement of the moving cylinder 31, the newrecovery retort 21 is attached to the cylinder shaft 24 of the insertioncylinder 23. With the contraction movement of the moving cylinder 31,the recovery retort 21 is moved forward in the cooling and vacuum purgechamber 3, and stops when the open face of the front end of the recoveryretort 21 reaches the end of the forward movement of the moving carriage36, in other words, a position just in front of the vacuum double door 2(the second stop point). At that time, the vacuum double door 2 isclosed.

After the interior of the cooling and vacuum purge chamber 3 ishermetically maintained by the operation of the vacuum door 32 at apoint in time when the recovery retort 21 reaches the second stop point,the vacuum valve 6 is opened, the vacuum pump 7 starts operating, andthe interior of the cooling and vacuum purge chamber 3 comes to have thesame degree of vacuum as the interior of the vacuum furnace 1.Thereafter, the opening and closing cylinder 15 starts operating, thevacuum double door 2 is opened, and the insertion cylinder 23 startsoperating to let the opening of the recovery retort 21 face the interiorof the vacuum furnace 1. In the vacuum furnace 1, the object to betreated is heat-treated under a proper degree of vacuum to producemetallic vaporized substances, and the vaporized substances flow intothe recovery retort 21 without going to the vacuum double door 2.Accordingly, the occurrence of the situation in which the vaporizedsubstances adhere to the vacuum double door 2 to lower and deterioratethe vacuum sealing capability thereof can be avoided.

After the completion of the recovery of the vaporized substances, therecovery retort 21 is pulled out to the second stop point by theoperation of the insertion cylinder 23, and thereafter the vacuum doubledoor 2 is closed by the operation of the opening and closing cylinder15. An inert cooling gas such as nitrogen gas is then supplied into thecooling and vacuum purge chamber 3, and the cooling and vacuum purgechamber 3 is cooled to a temperature at which there is no possibilitythat the recovered metal is oxidized and combusted. As described above,in the apparatus, after the vacuum furnace 1 and the cooling and vacuumpurge chamber 3 are blocked off by the vacuum double door 2, only theinterior of the cooling and vacuum purge chamber 3 is cooled while theinterior of the vacuum furnace 1 is maintained at a high temperature,which can omit wasteful time to cool the vacuum furnace 1 unlike theconventional case.

After the recovered metal is cooled fully, nitrogen gas or the like isfurther supplied into the cooling and vacuum purge chamber 3, and thepressure in the chamber is regulated so as to be equalized to theoutside pressure. After the completion of this pressure regulation, thevacuum door 32 is opened with the operation of the moving cylinder 31,and the recovery retort 21 is puled out to the first stop point. Therecovery retort 21 is removed from the insertion cylinder 23 there, andthe vaporized metal is recovered specially. After this, the aforesaidprocess is repeated.

Next, the structure of a route from the cooling and vacuum purge chamber3 to the vacuum pump 7 will be explained. In the apparatus, a method toprevent fine particles vaporized in vacuum in the vacuum furnace 1 fromflowing into the vaporized substance outlet 17 through the recoveryretort 21 and further into the seal portion of the vacuum valve 6 andthe vacuum pump 7 to lower the sealing capability of vacuum seal, or tocause a failure of the vacuum pump 7 is devised. Namely, the metallicnet 22 is put up at the outlet for vaporized substances of the recoveryretort 21, and a solid-type and liquid-type filters are placed doublybetween the vaporized substance outlet 17 and the vacuum valve 6.

The solid-type filter 4 is composed of a wire gauze filter, a ceramicball, or the like. When the suction force of the vacuum pump 7 is not sostrong, even only the solid-type filter 4 is sufficient, but if thesuction force exceeds a certain level, the fine particles pass throughthe solid-type filter 4 and reach the vacuum valve 6 and the vacuum pump7. Thus, herein, the liquid-type filter 5 is placed after the solid-typefilter 4. This liquid-type filter 5 recovers fine particles byintroducing them into a liquid or a liquid filter.

When the amount of file particles is small, the liquid-type filter 5only is sometimes used without using the solid-type filter 4, but whenthe amount of fine particles is large or when the size of a particle islarge, it is necessary to use both the solid-type filter 4 and theliquid-type filter 5.

There can omit operations requiring a long period of time in which thevacuum furnace is cooled and heated again, since the recovery retortfrom which vacuum-vaporized substances are recovered is pulled out ofthe vacuum furnace into the cooling and vacuum purge chamber, the vacuumfurnace and the cooling and vacuum purge chamber are blocked off by thevacuum door, and thereafter only the interior of the cooling and vacuumpurge chamber is cooled. As a result, the operation can be performedvery efficiently and at a low cost, which is effective in saving energy.

Since the recovery retort comes into contact with the body surface ofthe vacuum furnace via the vacuum door, most of the vaporized substancesproduced in the vacuum furnace get into the recovery retort, which iseffective in eliminating the possibility that the vaporized substancesadhere to the vacuum door to thereby lower its vacuum hermetic sealingcapability.

It is effective in preventing vaporized fine particles from reaching thevacuum valve and the vacuum pump to thereby avoid the occurrence of thesituation in which the vacuum sealing capability of the vacuum valve islowered or a failure of the vacuum pump is caused.

It is effective in continuing operating even if something is wrong withone vacuum door, since a vacuum door is structured doubly and even onlythe other vacuum door can perform its duty.

EXAMPLE 23

The diffusion of organic halides such as dioxins, PCB, and coplanar PCBto the environment and their influences are serious social problems. Forexample, noxious organic halides such as dioxins remain in heatedresidues (ashes, chars, carbon) resulting from combustion treatment andthermal decomposition treatment of wastes. Moreover, a highconcentration of dioxins are detected from soil and the like around arefuse incineration plant and an industrial waste disposal plant, forexample, and thus a harmful influence on residents' health causesserious anxiety. Furthermore, soil, sludge, and the like also containorganic halides.

As described above, organic halides such as dioxins, or heavy metalsremain in many cases in solids and liquids such as the heated residuesof wastes, soil and sludge under special conditions, or the like.

As a method for removing noxious substances containing organic halidesor heavy metals, a method of reducing the concentration of organichalides by heating an object to be treated containing organic halides ata high temperature or by subjecting it to melting treatment at a hightemperature of about 1500° C. is proposed. Such a method, however, hasdisadvantages that expensive and large-scale equipment is needed,running costs are high, and the like. Moreover, this method has adisadvantage of being unable to cope with dioxins produced while thetemperature of the object to be treated reaches the decompositiontemperature of dioxins from normal temperature. Effective treatmenttechnology for soil around incineration facilities and the like to whichorganic halides such as dioxins, As, Hg, Cd, Pb, Cr⁺⁶ and the like fall,has not been established.

When town refuse and the like are treated by combustion (incineration),the production of organic halides can be reduced if they can becombusted completely. It is extremely difficult, however, to completelycombust abundant and heterogeneous objects to be treated. Even ifcomplete combustion is possible, noxious organic halides such as dioxinsare produced until the object to be treated reaches a predeterminedtemperature.

Organic halides such as dioxins remain in a heated residue being aresidue resulting from heat treatment of the object to be treated suchas combustion or thermal decomposition, and the establishment of heattreatment technology for reducing the concentration of organic halidesremaining in the heated residue and removing them is demanded.

Incidentally, to produce dioxins, it is necessary that reactive chlorineatoms bonding with carbon of benzene nuclei and oxygen for bondingbenzene nuclei exist. It is thought that it is effective to control thequantities of these reactive chlorine atoms and oxygen in a thermaldecomposition furnace in order to suppress the production of dioxins atthe time of thermal decomposition. However, hitherto a thermaldecomposition furnace suitable for preventing the production of dioxinsfrom such a viewpoint has not been proposed. Especially, technology forrealizing the suppression of production of organic halides such asdioxins and coplanar PCB at relatively low temperatures (from normaltemperature to 500° C.) in the process of temperature rise to apredetermined heating temperature and the decomposition of organichalides remaining in a heated residue such as residual ashes or the likeat a low temperature has not been established yet.

There is a need to provide a soil producing method and a soil treatmentapparatus for producing clean soil from soil contaminated by organichalides such as dioxins.

There is a need to provide a treatment method and a treatment apparatuscapable of safely and certainly removing dioxins contained in a heatedresidue such as residual ashes, residual liquid, and soot and dust letout from refuse incineration facilities of local governments, factories,and the like, and soil, sludge, and the like contaminated by dioxins.

In view of the above, there is adopted the following structure.According to an aspect, a soil producing method for producing a secondsoil containing organic halides with a second concentration lower than afirst concentration from a first soil containing the organic halideswith the first concentration includes of introducing the first soil to ahermetic zone, and thermally decomposing at least a part of the organichalides by heating the first soil under reduced pressure. An object tobe treated is heated to a temperature not less than the decompositiontemperature of the organic halides, or a temperature not less than theboiling point thereof. As examples of organic halides, dioxins, PCB,coplanar PCB, and the like are given.

The method may further include reducing the concentration of halogencontained in a gaseous emission produced by the thermal decomposition ofthe soil. Thereby, a possibility of production or reproduction oforganic halides in the gaseous emission can be reduced.

A thermally decomposed residue of the first soil may be cooled after thehermetic zone is purged by a purge gas which is substantially organichalide-free and not capable of producing organic halides. As a result,organic halides such as dioxins can be prevented from being fixed in theresidue by cooling.

As configurations of the purge gas which is substantially organichalide-free and not capable of producing organic halides, gas of atleast one element selected from a group consisting of helium, neon,argon, krypton, xenon, nitrogen, and hydrogen, a mixed gas of theseelements, a gas with the above gas and the mixed gas as a mainconstituent, for example, can be given.

The thermally decomposing step may be performed in the hermetic zonewhere an oxygen concentration is controlled. Consequently, a change inthe amount of gaseous emission can be controlled, irrespective ofheterogeneity of the object to be treated, partial combustion, and thelike, and thus the gaseous emission can be treated more surely andefficiently. Moreover, the production of dioxins can be prevented byholding down oxygen concentration and halogen concentration.

According to another aspect, a soil producing method for producing asecond soil containing organic halides with a second concentration lowerthan a first concentration from a first soil containing the organichalides with the first concentration includes heating the first soil sothat at least a part of the organic halides are vaporized or decomposed,introducing a heated residue of the soil to a hermetic zone, and coolingthe heated residue of the soil after the hermetic zone is purge by apurge gas which is substantially organic halide-free and not capable ofproducing organic halides.

According to another aspect, in a soil producing method, soil containingorganic halides is thermally decomposed under reduced pressure. Underreduced pressure, a mean free path of a molecule is long, and anon-oxidizing atmosphere is maintained in the furnace, therebypreventing the production and reproduction of organic halides such asdioxins. Moreover, under reduced pressure, the partial pressure oforganic halides themselves is low, thereby making it possible to reducethe concentration of dioxins remaining in the heated residue.

Dioxins can be treated effectively by heat-treating soil, a heatedresidue, roasted articles, residual ashes, residual liquid, soot anddust, and the like containing residual dioxins, for example, from refusedisposal facilities, factories, and the like while pressure is reducedfrom normal pressure with an increase in temperature. Besides, theconcentration of halogen contained in a gaseous emission produced by thethermal decomposition of soil may be reduced.

According to another aspect, in a soil treatment apparatus, a soiltreatment apparatus for treating a soil containing organic halides orbeing capable of producing organic halides by heating, includes a meansfor heating the soil, a hermetic zone, a means for introducing a heatedresidue of the soil to the hermetic zone, a means for purging thehermetic zone by a purge gas which is substantially organic halide-free(which is short of organic halides), and a means for cooling the heatedresidue. Herein, regardless of combustion, thermal decomposition, orthermal decomposition under reduced pressure, after being heated, thesoil which is the object to be treated is purged and cooled in thehermetic zone. The purge means may introduce the purge gas afterpressure in the hermetic zone is reduced.

Moreover, the apparatus may further include a halogen trapping meanshaving a metal for forming compounds with halogen contained in gaseousemission produced by the heating of the soil or an adsorbent foradsorbing the halogen in the gaseous emission.

Besides, the apparatus may further include a reforming means forreforming the gaseous emission produced by the heating of the soil at afirst temperature such that dioxins are decomposed, and a cooling meansfor cooling the gaseous emission to a second temperature so that a risein the concentration of dioxins in the reformed gaseous emission issuppressed. As concerns the cooling means, rapid cooling by jetting oilto the gaseous emission is also recommended.

Namely, according to another aspect, in a treatment method, an object tobe treated containing organic halides is thermally decomposed underreduced pressure. Incidentally, if the object to be treated such assoil, burned ashes, or the like contains not only organic halides butalso heavy metals and the like, after the organic halides are treated,the temperature and pressure in the system are regulated to therebyvaporize the heavy metals. The vaporized metal may be condensed andrecovered by such a recovery chamber as described above. The gaseousemission produced by the pressure reduction or heating of the object tobe treated such as soil and burned ashes also may be introduced into atreatment system in the same manner.

Further, according to another aspect, a treatment apparatus for treatingan object to be treated containing organic halides or being capable ofproducing organic halides by heating includes a means for heating theobject to be treated, a hermetic zone, a means for introducing theheated residue to the hermetic zone, a means for purging the hermeticzone by a purge gas which is substantially organic halide-free (which isshort of organic halides), and a means for cooling the heated residue.

As the heating means, a combustion furnace for combusting the object tobe treated, a thermal decomposition furnace for thermally decomposingthe object to be treated, a reduced pressure thermal decompositionfurnace for thermally decomposing the object to be treated under reducedpressure can be named.

According to another aspect, in a treatment apparatus, an object to betreated is passed through a furnace capable of controlling thermaldecomposition temperature or through a plurality of reduced pressurefurnaces different in thermal decomposition temperature when beingsubjected to thermal decomposition (roasting) treatment while thepressure is being reduced from normal pressure. For example, the objectto be treated may be thermally decomposed in the furnace where thepressure is maintained almost constant but the temperature is beingchanged.

Further, a furnace capable of controlling thermal decompositiontemperature at which an object to be treated is subjected to thermaldecomposition treatment is provided, the pressure in the furnace ischanged from normal pressure to a predetermined degree of vacuum, andthus the degree of vacuum can be maintained. For example, the object tobe treated may be thermally decomposed in the furnace where thetemperature is maintained almost constant but the pressure is beingchanged.

Furthermore, a normal pressure furnace and a plurality of reducedpressure furnaces each for subjecting an object to be treated to thermaldecomposition treatment may be continuously provided, and the thermaldecomposition temperature in each of the furnaces may be set so as toincrease with progress to a later stage.

It further includes a halogen trapping means placed to connect with thereduced pressure furnaces and holding a metal for forming compounds withhalogen contained in a gaseous emission produced by the thermaldecomposition of the object to be treated or an adsorbent for adsorbingthe halogen in the gaseous emission therein. A portion of the halogentrapping means loaded, for example, with metals for trapping halogen, acatalyst for decomposing the halogen, or the like may be maintained atan almost constant temperature in the range of normal temperature toabout 1000° C., and more preferably in the range of about 400° C. toabout 1000° C. It is desirable to maintain a portion, at which halogenis adsorbed, at a low temperature.

Herein, a heated residue containing residual dioxins let out from wastedisposal facilities, factories, and the like may be treated while beingheated with a reduction in pressure. Roasted articles, residual ashes,residual liquid, soot and dust, and the like which contain residualdioxins let out from refuse disposal facilities, factories, and the likemay be treated while the pressure is reduced from normal pressure withan increase in temperature.

Herein, it is suitable that by introducing a gaseous emission into areducing means in a heating state placed at a gas outlet of ahermetically sealable thermal decomposition furnace, the gaseousemission is decomposed and reduced, then the concentration of at leastone gas of oxygen, oxide gas, chlorine, chloride gas downstream of thereducing means is measured, and that the temperature, pressure, oxygenconcentration, and the like in the thermal decomposition furnace iscontrolled according to the measured value.

Herein, organic halides are defined as what contains dioxins, PCB,coplanar PCB, DDT, trichloroethylene, trihalomethane, and the like (SeeFIG. 6).

Herein, unless not explained specially, polychlorinateddibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), andhomologues different from these in number of chlorine and substitutionposition are generically called dioxins. In addition, compounds in whichanother halogen such as fluorine or bromine is substituted for chlorinein dioxins are included in organic halides defined in the description.

To reduce the concentration of organic halides such as dioxins, PCB, andcoplanar PCB in the heated reside of the object to be treated, it isimportant to heat the object to be treated at such a temperature that atleast a part of such organic halides are decomposed and to cool theobject to be treated in an atmosphere with the lowest possibleconcentration of substances having organic halides and organic halideproducing capability.

Meanwhile, also as concerns a gaseous emission produced by heating ofthe object to be treated, it is desirable to reduce the concentration ofdioxins, for example, the concentration of substances such as halogencapable of producing dioxins to a minimum.

If organic halides coexist in a cooling atmosphere when the object to betreated is cooled, the organic halides are fixed in the object to betreated. If materials capable of producing organic halides coexist whenthe object to be treated is cooled, organic halides are composed orrecomposed in the process of cooling, and consequently organic halidesremain in a residue as well.

Accordingly, herein, in treating the object to be treated containingorganic halides or producing organic halides by heating, after heatingsuch as combustion or thermal decomposition, the heated residue iscooled in a state in which the concentration of substances havingorganic halides and organic halide producing capability is lowered. Forthis purpose, the heated residue may be cooled, for example, in anatmosphere purged with a cooling gas containing no material for organichalides. Therefore, it is desirable to use gas containing no halogen,oxygen nor organic compounds as a cooling gas, and, for example, raregases such as argon, nitrogen, and the like can be used.

As examples of the object to be treated, town refuse, burned ashes oftown refuse, soil, sludge, agricultural products, aquatic products,shredder dust, scrapped household appliances, various kinds of wastes,and the like, which are contaminated by organic halides such as dioxinsor PCB, can be given.

According to another aspect, a treatment method for treating an objectto be treated capable of producing organic halides by heating includesheating the object to be treated, introducing a heated residue to ahermetic zone, purging the hermetic zone by a purge gas which issubstantially organic halide-free and not capable of producing organichalides, and cooling the heated residue.

According to another aspect, a treatment method for treating an objectto be treated capable of producing organic halides by heating includesheating the object to be treated, introducing a heated residue to ahermetic zone, purging the hermetic zone by a purge gas which issubstantially organic halide-free (which is short of organic halides),and cooling the heated residue, where “organic halide-free” means ashortage of organic halides. As types of purge gas, a rare gas,nitrogen, hydrogen, or a mixed gas of these gases can be shown. Air alsocan be used as a purge gas as far as oxygen concentration does notmatter.

As types of heating of the object to be treated, for example,combustion, thermal decomposition, and the like can be given. Suchheating may be performed while oxygen concentration is being controlled.Thermal decomposition may be performed while the pressure in thehermetic zone is being controlled, for example, the pressure is reducedor raised. The purge gas may be introduced into the hermetic zone afterthe pressure in the hermetic zone is reduced.

Also for a gaseous emission produced by the heating of the object to betreated, treatment of lowering the concentration of organic halides suchas dioxins is performed.

As an example of such treatment, the gaseous emission may be reformed ata first temperature such that dioxins are decomposed, and the gaseousemission may be cooled to a second temperature so that a rise in theconcentration of dioxins in the reformed gaseous emission is suppressed.

Concerning cooling of the gaseous emission produced by the heating ofthe object to be treated, rapid cooling by jetting oil to the gaseousemission is also suitable, thereby making it possible to suppress therecomposition of organic halides, and to trap hydrocarbon and the likein the reformed gaseous emission.

Moreover, it is also suitable that the gaseous emission cooled byjetting oil is reheated to a high temperature such that organic halidessuch as dioxins are decomposed again, and thereafter rapidly cooled byjetting cooling water. The cooling water may be alkaline.

Further, the concentration of halogen such as chlorine contained in thegaseous emission produced by the heating of the object to be treated maybe lowered. For example, a halogen trapping device for trapping halogenin the gaseous emission may be placed at a stage subsequent to a thermaldecomposition furnace. As an example of the configuration of the halogentrapping device, a configuration in which metals such as iron, cuttingscrap, and/or chemical compounds such as calcium hydroxides or the likewhich react with chlorine contained in the gaseous emission to composechlorides are put in a chamber is given. A catalyst and the like forpromoting fixing reaction of halogen contained in the gaseous emissionand decomposition of organic halides in the gaseous emission may be putin the chamber. In addition, an adsorbent for adsorbing halogencontained in the gaseous emission may be put therein. A plurality ofstructures of halogen trapping devices described above may be combined.

When an adsorbent such as zeolite is used for trapping halogen, it isdesirable to maintain the adsorbent at the lowest possible temperaturein order to raise adsorptive efficiency. In this case, the gaseousemission is cooled in the chamber in which the adsorbent is put, and itis desirable to perform this cooling rapidly so that the retention timeof the gaseous emission in the range of temperatures at which organichalides such as dioxins are reproduced is shortened as much as possible.

Various kinds of treatments for lowering the concentration of organichalides such as dioxins contained in the gaseous emission describedabove may be used in plural combination.

According to another aspect, it is recommended that a treatmentapparatus for carrying out such treatments be provided with, forexample, a hermetic zone capable of holding the object to be treatedhermetically therein, a means for regulating the temperature of thehermetic zone, a purge means for purging gas in the hermetic zone, and acooling means for cooling the heated residue of the object to betreated. In addition, the pressure in the hermetic zone may be reduced.

The purge means may not only purge gas in the hermetic zone, but alsointroduce a purge gas after reducing the pressure in the hermetic zoneand exhausting the gas therein. This exhaust system can be used also forpressure reduction in the hermetic zone other than gas purge.

Further, a moving means for moving the object to be treated in thehermetic zone may be provided. As the moving means, a rotary kiln, ascrew conveyor, a tray pusher, a drawer, a roller house, or the like maybe provided.

A gas circulating device for circulating gas in the hermetic zone whileregulating the temperature of the gas may be provided. As an example ofthe gas circulating device, it is recommended that a bypass connected tothe hermetic zone (a chamber) is provided, and that a circulating pump,a temperature regulating device or a heat exchanger, a filter means fortrapping dust, mist, and the like contained in a gas stream, and thelike be provided in the bypass. They may be positioned in the order ofthe filter, the temperature regulating device, and the circulating pump.It is specially desirable to position the filter in a stage prior to thecirculating pump and the temperature regulating device. An oil film, forexample, may be used as a filter. The aforesaid treatment methods andtreatment apparatus are not limited to a reduced pressure thermaldecomposition furnace, and can be also applied to treatment in heatingfurnaces such as an incinerator and a normal pressure thermaldecomposition furnace.

For example, the treatment apparatus can be added in a stage subsequentto a conventional incinerator and normal pressure decomposition furnace.Thus, organic halides such as dioxins can be safely and effectivelyremoved from a burned residue produced in the incinerator in largequantities.

The diffusion of organic halides having toxicity to the environment is aserious problem, and the reconstruction of incineration facilities intonew treatment facilities requires tremendous costs and time, andmoreover the treatment of wastes produced day by day is also needed. Thetreatment apparatus and method can be applied also to existingincineration facilities as an incidental equipment. Consequently, it ispossible to treat an object to be treated having an organic halideproducing capability while utilizing the existing facilities.

According to another aspect, a soil producing method for producing asecond soil containing organic halides with a second concentration lowerthan a first concentration from a first soil containing the organichalides with the first concentration includes introducing the first soilto a hermetic zone, and thermally decomposing at least a part of theorganic halides by heating the first soil under reduced pressure.

It is desirable that a thermally decomposed residue of the first soil becooled after the hermetic zone is purged by a purge gas which issubstantially organic halide-free and not capable of producing organichalides.

This is because if organic halides coexist in a cooling atmosphere whenthe object to be treated is cooled, the organic halides are fixed in theheated residue of the object to be treated as described above. In orderto vaporize organic halides by heating or remove organic halides fromthe heated residue of the object to be treated which produces organichalides, it is important to purge heating atmosphere gas containingorganic halides or to cool the heated residue in the state in which theconcentration of substances having organic halides and organic halideproducing capability is lowered by pressure reduction or the like. As aresult, the concentration of organic halides remaining in the secondsoil which is the heated residue of the first soil can be lowered andthe organic halides can be removed by cooling the thermally decomposedresidue of the first soil in the state in which the concentration oforganic halides or the substances having organic halide producingcapability is lowered.

Incidentally, it is preferable to perform the thermal decomposition ofthe first soil in the hermetic zone where the oxygen concentration iscontrolled. For example, it is recommended that the oxygen concentrationin the hermetic zone be measured and the oxygen concentration in thehermetic zone be regulated according to the measured oxygenconcentration. Besides, the aforesaid control of oxygen concentrationmay be performed by introducing a reducing carrier gas or a reducingagent into the hermetic zone.

The aforesaid active control of oxygen concentration in the hermeticzone enables thermal decomposition in a stable state even when theobject to be treated is heterogeneous. Further, by performing thermaldecomposition in the hermetic zone where a reducing atmosphere ismaintained, the production of organic halides such as dioxins can besuppressed. Furthermore, a reduction in the pressure in the hermeticzone enables mean free paths of molecules to become longer and theprobability of production of organic halides such as dioxins to belowered.

When the aforesaid first soil contains metals such as heavy metals, themetals may be vaporized by heating the soil and reducing the pressure tothereby be recovered. Thus, even when the soil is contaminated bymercury, cadmium, zinc, lead, arsenic, or the like, such metals can beseparated and recovered from the soil. Hexavalent chromium, for example,can be reduced into trivalent chromium. Such recovery of metals can beperformed by the aforesaid recovery chamber. Not limited to treatment ofcontaminated soil, the treatment apparatus and method can be applied totreatment of burned ashes, sludge, waste water, agricultural products,aquatic products, and the like. Soil treated by the treatment apparatusand method contains a large amount of inorganic components such asporous carbon, and hence can be used not only as soil, but also as aneffective soil conditioner. Furthermore, it may be used being mixed withorganic substances such as leaf mold and compost.

EXAMPLE 24

FIG. 56 and FIG. 57 are diagrams showing an example of the treatmentapparatus. This treatment apparatus can treat soil, burned ashes, andthe like containing organic halides such as dioxins.

This treatment apparatus includes a reforming unit 72 and a recoveryunit 73 between a reduced pressure heating furnace 71 and an exhaustsystem. The exhaust system is composed of a booster pump 74, a watersealing pump 75 including a sealing liquid circulating system capable ofcontrolling pH, and a rotary pump 76. An exhaust gas treatment systemfor treating exhaust gas from the exhaust system is placed at a stagesubsequent to the exhaust system (FIG. 57).

The reduced pressure heating furnace 71 can heat the object to betreated while the pressure in the system is reduced by the exhaustsystem. The reduced pressure heating furnace 71 includes a chamber 71 afor housing the object to be treated, a heater 71 b for heating thechamber 71 a, a vacuum gauge 71 c for measuring the pressure in thechamber, a thermo-couple 71 d for measuring the temperature in thechamber, and a flow meter 71 e for controlling the flow rate of acarrier gas. It is recommended that nitrogen, a rare gas, hydrogen orthe like be used as the carrier gas as required. The oxygenconcentration in the system may be regulated according to the flow rateof the carrier gas. The carrier gas is used also as a cooling gas whichis organic halide-free for the heated residue of the object to betreated. A chamber 72 a in the reforming unit 72 is heated by a heater72 b, and can crack the gaseous emission from the object to be treatedcirculating in the chamber 72 a. Noxious substances such as dioxins,PCB, and coplanar PCB contained in the gaseous emission are decomposedby the reforming at a high temperature. In the treatment apparatus, thegaseous emission can be reformed under reduced pressure by providing thereforming unit between the reduced pressure heating furnace and theexhaust system. Moreover, in this example, a catalyst 72 c such asdecomposes organic halide, promotes decomposition, and suppressescomposition is put into the chamber 72 a. A catalyst in which asubstrate made of alumina or ceramics is impregnated with nickel is usedhere, but the type of catalyst can be selected as required. The reducedpressure heating furnace 71 and the reforming unit 72 are connected by apipe 71 f which is kept warm so that the gaseous emission is notcondensed. Moreover, herein, it is desirable to heat the object to betreated after the reforming unit 72 fulfills predetermined operatingconditions. When reforming is performed by heating, for example, it isrecommended that the object to be treated be heated in the reducedpressure heating furnace 71 after the temperature in the reforming unitreaches a set temperature at which the gaseous emission is reformed.Therefore, a means for detecting the temperature in the reforming unitand a means for heating the interior of the reduced pressure heatingfurnace according to the detected temperature may be provided. Moreover,a means for maintaining a set value such as a reforming temperature inthe reforming unit (for example, a memory), a means for detecting thetemperature in the reforming unit, and a means for comparing thedetected temperature and the set value and heating the interior of thereduced pressure heating furnace according to the result of thecomparison may be provided. The gaseous emission reformed in thereforming unit 72 is introduced to the recovery unit 73. The recoveryunit 73 includes a recovery chamber 73 a in which a tubular retort isput and a hermetic door 73 b which can be opened and closed andpartitions off the chamber 72 a of the reforming unit 73 and therecovery chamber 73 a. The hermetic door 73 b performs opening andclosing operations by a cylinder 73 c. The structure of the recoveryunit is the same as that in FIG. 8, FIG. 9, FIG. 42, and FIG. 43, forexample. Specifically, a retort is inserted from the recovery chamber 73c to the chamber 72 a side when the hermetic door 73 b is open. Thehermetic door 73 b is shielded and protected by the inserted retort.When the retort is exchanged, the retort is pulled out to the recoverychamber 73 a side, the hermetic door 73 b is closed, and a valve betweenthe recovery chamber and the exhaust system is closed, which makes itpossible to take the retort out and recover condensates whilemaintaining the states of the reduced pressure heating furnace 71 andthe reforming unit 72. Herein, also metals contained in the object to betreated can be separated from the object to be treated and recovered bythis recovery unit. For example, even when a heavy metal such as lead,zinc, or cadmium is contained in contaminated soil or burned fly ashes,it is heated to its boiling point or higher and vaporized under reducedpressure, and can be recovered in a metallic state in the recovery unit73. It is desirable to take the metal condensed in the retort out aftera non-oxidizing gas such as nitrogen is introduced into the recoverychamber and cools the metal.

Furthermore, this recovery chamber 73 a is cooled by a refrigerant suchas cooling water. This cooling has not only the function of condensingthe metal but also the function as means for rapidly cooling the gaseousemission reformed in the reforming unit. Thus, the recomposition oforganic halides such as dioxins in the gaseous emission can besuppressed.

The oil film filter 711 is placed between the recovery unit 73 and thebooster pump 74. Owing to this oil film filter 711, the gaseous emissionwhich has not been condensed in the recovery unit, dust, and fineparticles of the condensed metal are prevented from reaching the exhaustsystem.

The water sealing pump 75 and the rotary pump 76 are connected inparallel at a stage subsequent to the booster pump 74. Such an exhaustsystem can be used by switching according to the sequence of treatment.When soil is treated, for example, water, oil, and the like arecontained in the gaseous emission at the early stages of heating, inwhich case it is desirable to bypass the booster pump 74 and performexhaust operation by the liquid sealing pump 75. The water and oil inthe gaseous emission are trapped by sealing liquid in the liquid sealingpump. Incidentally, in this apparatus, alkaline aqueous solution is usedas the sealing liquid in the liquid sealing pump. Nitrogen oxides,sulfur oxides, and the like in the gaseous emission can be neutralizedby this sealing liquid. If the treatment progresses and the water andoil in the gaseous emission decrease in quantity, the exhaust system isswitched to the rotary pump 76 and the booster pump 74, whereby thepressure in the treatment system can be reduced. In this state, a metalsuch as zinc, lead, or the like is vaporized from the object to betreated and condensed in the retort in the recovery chamber. Theswitching of the exhaust system is not limited to the aforesaid example,and can be suitably performed as required.

An exhaust gas neutralizing unit 77, an activated carbon filter 78, andan exhaust blower 79 are placed at a stage subsequent to the exhaustsystem to treat exhaust gas from the exhaust system.

The exhaust gas from the exhaust system is showered by an alkalineaqueous solution in a spray tower 77. The aqueous solution for cleaningthe exhaust gas is sent again to the spray tower 77 via a neutralizingtank 77 a and a circulating pump 77 c. Moreover, the pH of the aqueoussolution is monitored by a pH meter, and the alkaline aqueous solutionis supplied from an alkali reservoir 77 e, whereby the pH of circulatingwater is kept alkaline. This aqueous solution is supplied also to asealing liquid circulating system of the liquid sealing pump 75. Theexhaust gas cleaned by the alkaline aqueous solution is filtered by theactivated carbon filter 78, and then exhausted to the outside by theexhaust blower 79. It should be noted that an analytical sample recoveryunit 80 is provided in order to monitor the concentrations of substancesin the gaseous emission and the exhaust gas in this example. The on-linequantitative analysis of components contained in the gaseous emissionalso can be performed. The above makes it possible to regulate thetemperature, pressure, oxygen concentration of treatment of the objectto be treated, the reforming temperature of the gaseous emission, andthe like according to detected results.

INDUSTRIAL AVAILABILITY

As explained above, herein, when a tube is inserted into a firstopening, a hermetic door is shielded from a first hermetic chamber by azone between a second opening and a third opening in a side face of thetube, a gaseous emission can be prevented from condensing at thehermetic door or adhering thereto. Also when packing made of resin orthe like is provided at a seal portion of the hermetic door, forexample, the seal portion of the hermetic door can be prevented frombeing damaged by heat of the gaseous emission. Accordingly, the hermeticsealing capability of the hermetic door can be maintained. As describedabove, in a treatment apparatus, an interface from the first hermeticchamber to the outside is realized by the hermetic door and the tube.

In the treatment apparatus, even when a second hermetic chamber isopened and the tube is taken out, the hermetic sealing capability of thehermetic door is maintained, and hence the leakage of outside air intothe first hermetic chamber can be prevented. Accordingly, the tube canbe taken out while temperature conditions or pressure conditions in thefirst hermetic chamber are maintained. Hitherto, the treatment apparatushas needed to be stopped in order to take condensates out, which haslowered the productivity of treatment. Continuous operation of thetreatment apparatus and a rise in the productivity of treatment areenabled.

1. A treatment method, comprising: heating a treatment target objectunder reduced pressure in a hermetic zone to vaporize a component of thetreatment target object; and opening a hermetic door and inserting atube from a side of a treatment system for the vaporized componentadjoining the hermetic zone with the hermetic door therebetween suchthat the tube shields the hermetic door from the hermetic zone tointroduce the component vaporized from the treatment target object tothe treatment system side.
 2. The treatment method as set forth in claim1, further comprising cooling the tube to condense the vaporizedcomponent from the treatment target object.
 3. The treatment method asset forth in claim 1, further comprising decomposing the componentintroduced to the treatment system.
 4. The treatment method as set forthin claim 1, further comprising absorbing, by an absorbent, the componentintroduced to the treatment system.
 5. A treatment method, comprising:heating a treatment target object in a hermetic zone to thermallydecompose a component of the treatment target object; and opening ahermetic door and inserting a tube from a side of a treatment system fora component of a gaseous emission produced by the thermal decompositionadjoining the hermetic zone with the hermetic door therebetween suchthat the tube shields the hermetic door from the hermetic zone tointroduce the gaseous emission to the treatment system side.
 6. Atreatment method, comprising: introducing a treatment target object intoa hermetic zone; reducing a pressure in the hermetic zone to extract acomponent of the treatment target object; and opening a hermetic doorand inserting a tube from a side of a treatment system for the extractedcomponent adjoining the hermetic zone with the hermetic doortherebetween such that the tube shields the hermetic door from thehermetic zone to introduce the extracted component to the treatmentsystem side.
 7. A treatment method, comprising: heating a treatmenttarget object containing a first metal under reduced pressure in a firsthermetic zone to vaporize the first metal; inserting a tube from asecond hermetic zone adjoining the first hermetic zone with a hermeticdoor therebetween such that the tube shields the hermetic door from thefirst hermetic zone; and cooling the tube to condense the first metal.8. A soil treatment method, comprising: heating a soil containing afirst metal under reduced pressure in a first hermetic zone to vaporizethe first metal; inserting a tube from a second hermetic zone adjoiningthe first hermetic zone with a hermetic door therebetween such that thetube shields the hermetic door from the first hermetic zone; and coolingthe tube to condense the first metal vaporized from the treatment targetobject.
 9. The treatment method as set forth in claim 8, furthercomprising cooling, by a cooling gas which is substantially organichalide-free, a heated residue of the soil.
 10. A soil treatment method,comprising: heating a soil containing a moisture, an organic substance,and a first metal in a first hermetic zone to vaporize the moisture andto perform one of vaporizing and thermally decomposing of the organicsubstance; opening a first hermetic door and inserting a tube from aside of a treatment system for the moisture and one of the organicsubstance and a thermal decomposition product of the organic substanceconnected to the first hermetic zone with the first hermetic doortherebetween such that the tube shields the first hermetic door from thefirst hermetic zone to introduce the vaporized moisture and one of thevaporized organic substance and the thermal decomposition product of theorganic substance to the treatment system side; vaporizing the firstmetal after the vaporization of the moisture and one of the vaporizationand the thermal decomposition of the organic substance; opening a secondhermetic door and inserting a tube from a side of a second hermetic zoneadjoining the first hermetic zone with the second hermetic doortherebetween such that the tube shields the second hermetic door fromthe second hermetic zone to introduce the vaporized first metal to thesecond hermetic zone; and cooling the tube to condense at least thefirst metal.
 11. The treatment method as set forth in claim 10, whereinthe thermally decomposing of the organic substance and the vaporizing ofthe first metal are performed under reduced pressure.
 12. The treatmentmethod as set forth in claim 10, further comprising cooling, by acooling gas which is substantially organic halide-free, the soil afterthe vaporizing of the first metal.